Time left to be engaged in task? What a laugh! (7)
I believe the answer is:
chortle
'what a laugh' is the definition.
(chortling is a kind of laughing)
'time left to be engaged in task?' is the wordplay.
'time' becomes 'lt' (I can't justify this - if you can you should give a lot more credence to this answer).
'left' is a reversal indicator.
'to be engaged in' means one lot of letters goes inside another.
'task?' becomes 'chore' ('chore' can be a synonym of 'task').
'lt' reversed gives 'tl'.
'tl' put within 'chore' is 'CHORTLE'.
Can you help me to learn more?
(Other definitions for chortle that I've seen before include "Chuckle gleefully" , "Titter" , "Laugh softly" , "Noisy gleeful laugh" , "Laugh out loud" .)