Woodland deity in NY given speed (5)
I believe the answer is:
nymph
'woodland deity' is the definition.
(I've seen this in another clue)
'ny given speed' is the wordplay.
'given' is a charade indicator (letters next to each other).
'speed' becomes 'mph' (miles per hour).
'ny'+'mph'='NYMPH'
'in' acts as a link.
(Other definitions for nymph that I've seen before include "Demigoddess" , "Mythological spirit of nature imagined as a beautiful maiden" , "Larva of aquatic insect" , "Goddess - larval form" , "Young dragonfly" .)