emasculate

in the metaphorical sense, this may very occasionally be the word you mean, but too often it indicts something or someone (often a woman) for a process that depends just as importantly on a man's willingness to be emasculated, and unflatteringly implies that he is a passive victim. No parallel terms exist relating to women for "emasculate," "unman," and "castrate." For sex-neutral terms, consider disarm, disable, weaken, incapacitate, undermine, deprive of courage/strength/vigor/power. See also castrate/castrating (metaphor), unman.