Dry enough exercising dog (9)
I believe the answer is:
greyhound
'dog' is the definition.
(greyhound is a kind of dog)
'dry enough exercising' is the wordplay.
'exercising' is an anagram indicator.
'dry'+'enough'='dryenough'
'dryenough' with letters rearranged gives 'GREYHOUND'.
(Other definitions for greyhound that I've seen before include "slender runner?" , "Dog trained for racing on tracks" , "racer" , "Fast-moving dog" , "Speedy dog" .)