Mischievous sprite (3)
'mischievous sprite' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for elf that I've seen before include "Fairy, pixie" , "Robin Goodfellow?" , "He causes mischief" , "Imp-like being" , "Pixie (able to cobble?)" .)
(Other definitions for imp that I've seen before include "pickle" , "Small devil or sprite" , "Pixie" , "Small demon" , "A small mischievous devil" .)
(Other definitions for puck that I've seen before include "one spun across the ice" , "Fairy - ice hockey "ball"" , "Mischievous sprite or disc for ice hockey" , "In plentiful supply" , "Disc used in ice-hockey" .)
'mischievous sprite' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for gremlin that I've seen before include "Mischievous goblin" , "Aerial imp" , "One sabotages" , "Troublemaker (in the machinery?)" , "Mischievous machine saboteur" .)