Get on with five in a whirl? (7)
I believe the answer is:
advance
'get on' is the definition.
(synonyms)
'five in a whirl?' is the wordplay.
'five' becomes 'V' (Roman numeral).
'in' is an insertion indicator.
'whirl?' becomes 'dance' (whirl can mean to dance around).
'a'+'dance'='adance'
'v' put into 'adance' is 'ADVANCE'.
'with' is the link.
(Other definitions for advance that I've seen before include "Move forward like army or loan against wage" , "necessary to be recognised?" , "Payment ahead of due date (1'7)" , "Move froward as army does" , "capital" .)