I know there exists already "suppressing a smile" or "stifling a smile", but I feel that those phrases imply a lack of a smile. In this situation, something is funny, but the character is trying to pretend that it is not in an almost sarcastic/playful manner. A more visual description: pursed lips in a smile, with a scrunched nose.
1You could always use more emphatic descriptions of trying to hide it. Try thinking about what your face might do if, say, you hear something funnier than 24– user170231Dec 27, 2022 at 20:40
12"keep a straight face"?– davidbakDec 28, 2022 at 1:47
2Not specific to only this example, but 'poker-faced' fits nicely– mcalexDec 28, 2022 at 3:39
4What's so funny about Biggus Dickus?– Comic Sans SeraphimDec 28, 2022 at 14:18
2This probably belongs in English Language under the, ummm, "phrase for" tag– Owen ReynoldsDec 29, 2022 at 2:41
Concision sacrifices clarity.
Or, to be more clear, using an obscure phrase or adjective is likely to leave the reader unsure of your intent, trying to parse what you mean. You are better off being clear with more words.
People that read for fun don't mind reading.
So this might work:
Trying unsuccessfully to stifle a smile, with tightly compressed lips and a sparkle of laughter in his eyes.
Readers are not trying to get through your story as quickly as possible. As a writer, your job is to assist your reader's imagination, so they see the details you see. As Einstein said about scientific explanations, they should be made as simple as possible, but not simpler.
This applies here. Avoid redundancy, find the most economical and poetic way to convey the most important defining details of the image in your mind, but not at the expense of failing to convey those details.
Write it long, and then find ways to trim it, excise redundancy, and rearrange it to give it more power. Make different word choices, or sentence structures. But don't sacrifice the imagery. Readers don't mind reading.
Honestly I really like "trying not to smile." I have seen that used in the situation you describe, and use of the word "trying" conveys that perhaps the person wasn't wholly successful at the project of not smiling.
If you want something like "suppressing a smile" but making it clear that the smile is still evident, you could use "half-suppressing a smile", "attempting to suppress a smile" or even "failing to suppress a smile". You could even follow the example of Conan Doyle and have your character "fail to entirely suppress a smile".
Depending on what you really intend here, you could also describe it more visually. How would this mock-seriousness appear to the other characters? Perhaps some vestige or secondary expression gives the game away? For example,
"She kept her tone serious, but she couldn't stop the corners of her mouth turning up"
"His face was impassive, but his eyes twinkled with amusement"
Deadpan, dry humour, or dry-wit humour is the deliberate display of emotional neutrality or no emotion, commonly as a form of comedic delivery to contrast with the ridiculousness or absurdity of the subject matter. The delivery is meant to be blunt, ironic, laconic, or apparently unintentional.
Trying to stifle a smile might result in a smirk, with half of the mouth serious without smile, the other side of the mouth in a slight grin.
The idiom is "keeping a straight face". Variants are common such as "kept a straight face" or "with a straight face". A dictionary link: to manage to stop yourself from smiling or laughing
It's not simply "not smiling". It's about visibly trying not to smile. This page about keeping a straight face has common stuff: slowly taking a deep breath, pursing lips, jaw clenching, check biting, a hand over the mouth, faking a cough, or looking at the floor. "Brick struggled to keep a straight face" lets us know we can see him doing that sort of thing.
"Straight" can be a problem word, meaning not gay. But I think we're safe here: the "straight" part is probably about managing to keep one's mouth in a straight line.
The question is about failing to keep a straight face.– AmadeusDec 29, 2022 at 12:38
1@Amadeus Exactly "tried to keep a straight face" is also an answer! Dec 29, 2022 at 15:47
It comes from theatre and stage when the worst thing that could happen in the middle of a serious scene was that the corpse got a fit of the giggles. It implies ultimate failure to suppress the giggles rather than actual success.
For example, the guards in the Biggus Dickus scene are corpsing.
It's also probably not the word you want.
On Saturday Night Live it’s called “breaking”, as in “breaking character.”
Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center.– Community BotDec 29, 2022 at 10:58
@Community the citation is in the hyperlink. Dec 29, 2022 at 15:24
@JacobKrall links can die, and following them and finding the relevant part is an extra step. That's why we like to write the important parts in the answers. Maybe you can find a paragraph from your source and add it here? (editing with some [...]'s is allowed) Dec 29, 2022 at 16:24
Bite one's lip
This would be used when a situation is unintentionally funny where a person doesn't want to laugh and cause embarrassment.
4"Biting your lip" normally means withholding some criticism or objection. collinsdictionary.com/dictionary/english/bite-ones-lip– kaya3Dec 28, 2022 at 20:37