1.NounA small, common warbler, of species Phylloscopus collybita, with yellowish-green plumage that breeds throughout northern and temperate Europe and Asia.
2.NounAny of several other species of the same genus.
3.InterjectionThe song of the chiffchaff.
"I thought I heard something singing chiffchaff, chiffchaff. So I had a look and there was a chiffchaff."