to embarrass or disconcert (somebody)
He imagined himself to be … accomplished … because he could spell his own name; and was marvellously discomfited that I didn't think the same — Emily Brontë
to frustrate the plans of (somebody)
discomfiture /-fichə/ noun
[Middle English discomfiten from Old French desconfit, past part. of desconfire, from dis- + confire: see comfit]