OP I have been playing down what I do and what I have achieved my entire life, in a probably very female way.
At school, when asked what results I got 'oh, I did quite well' to mean yes, I got outstanding results.
Out clubbing, when asked about where you go to college, don't mention you are at Cambridge.
Don't mention your PhD or put your title, that makes you look 'snobby' apparently.
Say things like 'I work at the university' so you could be a cleaner, even though you are not. Do you think my lovely work cleaner says 'I work at the university' in a vague way? Of course not, she says 'I'm a cleaner'!
Pretend to work part-time/in a lesser role/don't say 'academic'/don't say 'lecturer' even though it's your actual bloody job title.
Obviously don't become a Professor, because then you'll be totally embarrassing and have to wear jeans all the time to prove you are an ordinary person (joke: even though of course you are anyway).
It's very tiring and tiresome, one reason I loved going back into academia in my late twenties was I got to hang out with people for whom this was no big deal, and being a clever woman was perfectly normal and not something to be remarked on or hidden.
Weirdly, even the lovely female Professors I know still try to make out it was all luck/they aren't that clever. I have never ever met a male Professor who does this. All except one who totally owns it, I aspire to be like that now.
It's actually very destructive for females within the academic system, as they continually downplay their results, suffer from imposter syndrome, don't get promoted quite as quickly (as less likely to put themselves forward/less identified as candidates), have to do better than many males who, despite, 50/50% at PhD gender levels, by Professor level, there's about 20% women.