Be a diversion, and an inspiration to (5)
I believe the answer is:
amuse
'be' is the definition.
The definition and answer can be both to do with social activities as well as being verbs in their base form.
Perhaps you can see an association between them that I can't see?
'a diversion and an inspiration to' is the wordplay.
I cannot really see how this works, but
'a' is found in the answer.
'inspiration' could be 'muse' (a muse is someone's inspiration) and 'muse' is found within the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for amuse that I've seen before include "Cause to laugh or smile" , "Cause mirth - distract" , "Enliven" , "Delight" , "Make (someone) laugh" .)