Modest, bowing out (8)
I believe the answer is:
retiring
This clue could be a double definition.
'modest' is the first definition.
(thesaurus)
'bowing out' is the second definition.
The definition and answer can be both to do with social activities as well as being present participle verbs.
Maybe they are linked in a way I don't understand?
Can you help me to learn more?
(Other definitions for retiring that I've seen before include "Shy and fond of being on one's own" , "Shy - going to bed" , "Like an unassertive person" , "of unobtrusive aspect" , "taking clothes off etc?" .)