Grey-haired dolt wasting time cycling (3)
I believe the answer is:
old
'grey-haired' is the definition.
(similar in meaning)
'dolt wasting time cycling' is the wordplay.
'wasting' suggests deleting specific letters.
'time' becomes 't' (abbreviation).
'cycling' indicates an anagram.
'dolt' with 't' taken out is 'dol'.
'dol' with letters rearranged gives 'OLD'.
(Other definitions for old that I've seen before include "Much-used" , "Getting on" , "Venerable" , "SECOND PART OF 14" , "Obsolete" .)