noun
slippery as an eel; elusive person
Idiomatic expression describing a person who is evasive, hard to pin down, or slippery in character. Literally 'gourd catfish', evoking the image of trying to catch a slippery catfish with a smooth gourd.
あの政治家は瓢箪鯰で、質問にまともに答えない。
That politician is as slippery as an eel and never answers questions directly.
Means 'hard to grasp' or 'elusive' in a more general sense, while 瓢箪鯰 specifically compares a person to a slippery catfish.
From 瓢箪 (ひょうたん, 'gourd') and 鯰 (なまず, 'catfish'), referring to the difficulty of catching a slippery catfish with a smooth gourd, used metaphorically for an elusive person.