n.
a small wingless jumping insect which feeds on the blood of mammals and birds.
[
Pulex irritans (
human flea) and other species, order Siphonaptera.]
Phrase
-
(as)
fit as a flea
in very good health. - a flea in one's ear
a sharp reproof.
Etymology
OE flēa, flēah, of Gmc origin.
