unnerving

verb (used with object), un·nerved, un·nerv·ing.

1. to deprive of courage, strength, determination, or confidence; upset: Fear unnerved him.

verb

1. (tr) to cause to lose courage, strength, confidence, self-control, etc

v.1620s, “to destroy the strength of,” from un- (2) + nerve. Meaning “to deprive of courage” is recorded from 1704. Related: Unnerved; unnerving.