confound

Concise Oxford English Dictionary © 2008 Oxford University Press:
confound/kənˈfaʊnd/

▶verb

• 1 surprise or confuse.

  ■ prove wrong.

  ■ defeat (a plan, aim, or hope).

• 2 (often be confounded with) mix up with something else.

▶exclamation informal, dated used to express annoyance: oh confound it, where is the thing?

– origin ME: from OFr. confondre, from L. confundere ‘pour together, mix up’; cf. confuse.