godan verb (-ru), transitive verb
nibble at; gnaw
Literally to bite off small pieces, often used for animals or casual eating.
ネズミがチーズを食い齧っている。
A mouse is nibbling at the cheese.
彼はパンの耳を食い齧りながら歩いていた。
He was walking while gnawing on the crust of the bread.
godan verb (-ru), transitive verb
have a smattering of knowledge; dabble in
Metaphorical use: to have only superficial or partial knowledge of a subject, like nibbling at it.
彼は経済学を食い齧っただけの素人だ。
He's just an amateur who has only a smattering of economics.
いろんな分野を食い齧るより、一つを深く学びなさい。
Instead of dabbling in many fields, learn one deeply.