Parasitic insect (4)
'parasitic insect' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for flea that I've seen before include "Circus insect?" , "Little jumper?" , "Bloodsucking parasite" , "In your ear, this insect is a rebuke" , "Wingless, jumping insect" .)
'parasitic insect' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for louse that I've seen before include "Wingless parasite" , "Wingless bloodsucking insect" , "Wingless parasitic insect" , "Human parasite" , "Insect -- nasty character, undeserving of respect" .)