不該
bù​gāi

should not

bù​gāi should not
  1. 不 bù adverb
    not
    Negative adverb used before verbs, adjectives, and other adverbs to indicate negation; also used as a bound-form prefix to form terms with opposite meanings
  2. 该 該 gāi auxiliary
    should
    should; ought to; to be supposed to; to be likely to

bù​gāi to owe nothing
  1. 不 bù adverb
    not
    Negative adverb used before verbs, adjectives, and other adverbs to indicate negation; also used as a bound-form prefix to form terms with opposite meanings
  2. 该 該 gāi
    to owe
    to owe (money or a debt)