As one goes for identity, person becomes oppressive (5)
I believe the answer is:
humid
'oppressive' is the definition.
(thesaurus)
'as one goes for identity person' is the wordplay.
I cannot really understand how this works, but
'one' could be 'i' (Roman numeral) and 'i' is located in the answer.
'person' could be 'md' (MD is an example) and 'md' is found in the remaining letters.
This explanation may well be incorrect...
'becomes' acts as a link.
Can you help me to learn more?
(Other definitions for humid that I've seen before include "Rather wet" , "Moist, warm (weather)" , "Describes air that contains a great deal of water vapour" , "Moist (atmosphere)" , "Close" .)