| Noun | 1. | gnat - any of various small biting flies: midges; biting midges; black flies; sand fliesdipteran, dipteron, dipterous insect, two-winged insects - insects having usually a single pair of functional wings (anterior pair) with the posterior pair reduced to small knobbed structures and mouth parts adapted for sucking or lapping or piercing biting midge, no-see-um, punkey, punkie, punky - minute two-winged insect that sucks the blood of mammals and birds and other insects midge - minute two-winged mosquito-like fly lacking biting mouthparts; appear in dancing swarms especially near water psychodid - a fly of the family Psychodidae Phlebotomus papatasii, sand fly, sandfly - any of various small dipterous flies; bloodsucking females can transmit sandfly fever and leishmaniasis black fly, buffalo gnat, blackfly - small blackish stout-bodied biting fly having aquatic larvae; sucks the blood of birds as well as humans and other mammals |
| 2. | gnat - (British usage) mosquito mosquito - two-winged insect whose female has a long proboscis to pierce the skin and suck the blood of humans and animals |