曖昧な、両義に取れる,多義の,あいまいな,不明瞭な

ambiguous
vague

aving or expressing more than one possible meaning, sometimes intentionally:
His reply to my question was somewhat ambiguous.

Japanese has a lot of vague expressions.
日本語は曖昧な表現が多い。

You should avoid ambiguous phrases in order to be understood by others.
言ってることが他人に伝わる為に曖昧な表現を避けたほうがいい。