Nigel's getting about, being unmarried (6)
I believe the answer is:
single
'being unmarried' is the definition.
(similar in meaning)
'nigel's getting about' is the wordplay.
'getting about' is an anagram indicator.
'nigels' is an anagram of 'SINGLE'.
(Other definitions for single that I've seen before include "A hit for one run in cricket" , "Sort of person" , "Short pop record" , "Only one; record" , "Individual - unmarried" .)