Love to come together briefly to spin a little mischief! (7)
I believe the answer is:
gremlin
'a little mischief' is the definition.
(mischief can mean someone who causes mischief)
'love to come together briefly to spin' is the wordplay.
'love' becomes 'nil' (love and nil mean zero in cricket and football).
'to come together' becomes 'merge' (merge means to join together).
'briefly' means to remove the last letter.
'to spin' says the letters should be written backwards.
'nil'+'merge'='nilmerge'
'nilmerge' with its final letter taken away is 'nilmerg'.
'nilmerg' backwards is 'GREMLIN'.
(Other definitions for gremlin that I've seen before include "One sabotages" , "Fault-causing sprite" , "Troublemaking goblin" , "Imp causing mechanical problems?" , "cause of trouble for airmen" .)