Record group of men roller-skating (5)
I believe the answer is:
enrol
'record' is the definition.
(I know that enrol is a kind of register)
'group of men roller-skating' is the wordplay.
'group of' indicates a hidden word (group of letters from the clue).
'ENROL' is hidden within 'men roller skating'.
(Other definitions for enrol that I've seen before include "Join up, sing on" , "Recruit" , "Record" , "Sign on, being a loner" , "Register officially" .)