Old man greedy now and then (4)
I believe the answer is:
aged
'old' is the definition.
(similar in meaning)
'man greedy now and then' is the wordplay.
'now and then' means one should take alternating letters (letters taken on a regular basis, now and then).
'man'+'greedy'='mangreedy'
The alternate letters of 'mangreedy' are 'AGED'.
(Other definitions for aged that I've seen before include "Elderly" , "Very old, person or wine" , "way over the hill" , "Senior" , "Old or ancient" .)