Colloquial, somewhat derogatory term for frogs and toads, often used in a dismissive or vulgar tone. Can refer specifically to the wrinkled frog (Glandirana rugosa), the Asian grass frog (Fejervarya limnocharis), or the Japanese toad (Bufo japonicus).
There was a damn frog in the garden.
That stupid frog is croaking again.
Compound of 糞 (くそ, 'excrement; damn') and 蛙 (かえる, 'frog'). The prefix 糞 adds a vulgar, derogatory nuance, similar to English 'damn' or 'shitty'.