Participates in, as one promises (7)
I believe the answer is:
engages
This could be a double definition.
'participates' is the first definition.
The definition and answer can be both to do with social activities as well as being verbs in their -s form.
Perhaps you can see a link between them that I don't see?
'as one promises' is the second definition.
The answer and definition can be both to do with communicating as well as being verbs in their -s form.
Maybe you can see an association between them that I don't see?
'in' is the link.
Can you help me to learn more?
(Other definitions for engages that I've seen before include "books" , "Employs, hires" .)