ボキャ貧 (ぼきゃひん, bokyahin) is a Japanese slang term that means “having a poor vocabulary”. In particular, it describes people who always rely on verstile words such as “やばい” (yabai. “sick/cool/oh gosh”) and “すごい” (sugoi, “awesome”) to describe anything. As of 2020, it might be slightly getting outdated, but still used on social media.
The word consists of the two parts “ボキャ” and “貧“. The former stands for “ボキャブラリー”, a loan word from “vocabulary” in English. The kanji character “貧 (ひん)” means “poor”, as in “貧しい” meaning “poor” and “貧困” meaning “poverty”. See other Japanese portmanteau words (words that combine parts of multiple words) in the related post here.
A: How was the party yesterday?
B: It was so sick and awesome.
A: You have such a poor vocabulary.
Because I have a poor tastebud and a poor vocabulary, I can say nothing but “おいしい (tasty)” whatever I eat.
(Note) 味音痴 describes a person who have a poor tastebud. Here, 味 means “taste” and 音痴 means “poor at understanding”. However, when 音痴 usually means “poor at singing”; see the related post below.