bedbug

Short definition from Wiktionary

Noun

1. 1
   A small nocturnal insect pest of humans, of species Cimex lectularius (common bedbug) and Cimex hemipterus (tropical bedbug) that feeds on the blood of humans during sleep.
2. 2
   Any similar insect of family Cimicidae, that feeds on the blood of humans and certain other warm-blooded animals.