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vague; ambiguous; unclear
shady; disreputable
fuzzy
彼の返事はいつも曖昧で困ります。
His answers are always vague and troublesome.
曖昧な表現は誤解を招きやすいので注意だ。
Vague expressions easily lead to misunderstandings.
契約書の曖昧な部分を確認しよう。
Let's check the ambiguous parts of the contract.