also: びんぼうした
noun
poor person's taste; unsophisticated palate
Colloquial term for someone who cannot tell good food from bad, often because they are used to cheap or simple meals. Can be self-deprecating or teasing.
彼は貧乏舌だから、高い料理の味がわからない。
He has an unsophisticated palate, so he can't appreciate expensive food.
私、貧乏舌で、コンビニのおにぎりで十分満足しちゃうんだよね。
I have a poor person's taste; I'm perfectly happy with convenience store rice balls.
味音痴 is a more direct and slightly harsher term for someone with no sense of taste, while 貧乏舌 specifically implies a palate dulled by a poor or simple diet.
Compound of 貧乏 (poverty) and 舌 (tongue), literally 'poverty tongue'. The exact origin is uncertain, but it likely arose as a colloquial expression for a palate accustomed to cheap food.