Retire and start to get going? (7)
I believe the answer is:
turning
'going?' is the definition.
(going is a kind of turning)
'retire and start to get' is the wordplay.
'retire' becomes 'turn in' (synonyms).
'and' means one lot of letters go next to another.
'start to' suggests taking the first letters.
The first letter of 'get' is 'g'.
'turnin'+'g'='TURNING'
(Other definitions for turning that I've seen before include "Deviation" , "Side-road; (leaves) changing colour" , "Side road (from main road)" , "Rotating; going bad" , "Changing allegiance" .)