Shows nominal willingness to make one's mark as a member (5,2)
I believe the answer is:
signs on
'shows nominal willingness' is the definition.
Although both the answer and definition are verbs in their -s form, I cannot see how one could define the other.
'one's mark as a member' is the wordplay.
I cannot really understand how this works, but
'mark' could be 'sign' (synonyms) and 'sign' is found within the answer.
'as' could be 'so' (I've seen this in other clues) and 'so' is found in the answer.
A single letter 'n' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
'to make' acts as a link.
Can you help me to learn more?
(Other definitions for signs on that I've seen before include "Employs" , "Hires" .)