IPA: /ˈɡɪɡlər/
KK: /ˈɡɪɡlər/
A person who laughs in a quiet and silly way.
The giggler couldn't stop laughing during the movie.
Giggler → The word is formed from "giggle" (of imitative origin, representing a light, silly laugh) and the suffix "-er" (meaning a person who performs an action). A giggler is a person who giggles or laughs lightly and silly.
Think of someone who is 'performing' the action of giggling — that's why a giggler is a person who giggles.