not wearing or removing clothes

undressed

un‧dressed /ˌʌnˈdrest◂/ BrE AmE adjective
[Word Family: noun: ↑dress, ↑dresser, ↑dressing; adjective: ↑dressed ≠ ↑undressed, ↑dressy; verb: ↑dress ≠ ↑undress]
1. [not before noun] not wearing any clothes:
He started to get undressed (=to take his clothes off).
2. an undressed wound has not been covered to protect it
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THESAURUS
▪ naked not wearing any clothes or not covered by clothes - used especially when this seems rather shocking: a naked man | He got out of bed naked, and answered the telephone. | his naked chest
▪ have nothing on/not have anything on to not be wearing any clothes. This phrase is very commonly used in everyday English instead of saying that someone is naked: Can you wait a minute? I've got nothing on! | The little boy didn’t have anything on when he answered the door!
▪ bare used about feet, legs, arms etc that are not covered by clothes: The sand was too hot to walk on in bare feet.
▪ nude naked – used especially when talking about naked people in paintings, films etc: a nude portrait of his wife
▪ undressed [not before noun] not wearing any clothes, especially because you have just taken them off in order to go to bed, have a bath etc: Sara was undressed and ready for bed but Jenny was fully clothed. | Wearily she got undressed and stepped into the shower.
▪ topless if a woman is topless, she is not wearing any clothes on the upper part of her body, so that her breasts are not covered: a topless waitress
▪ in the nude not wearing any clothes: Men and women swam together in the nude and thought nothing of it.
▪ in your birthday suit informal humorous not wearing any clothes: He likes to sleep in his birthday suit. He says pyjamas are uncomfortable.
▪ go commando informal humorous to not wear any underwear: In summertime, he likes to go commando.
▪ in the buff informal not wearing any clothes - a very informal use: a beach where you can sunbathe in the buff