That undervalues; depreciatory.

Judging adversely or malevolently.

(un-, prefix1 affix 1.)

Not properly or fully appreciative.

Characterized by caution or moderation; (esp. of an estimate) purposely low for the sake of caution.

Not appreciative; wanting in appreciation.

Rhetoric. Characterized by meiosis (meiosis, n. 1a).

Of a line or speech, remark, etc.: trivial, insignificant; (also) delivered in a casual way; understated or played-down, often for increased…

Baseball. Of a pitcher: pitching low balls.