(DICTIONARY.COM)

Definitions for flummox Informal.

to bewilder; confound; confuse.

Citations

There are things you do that you later learn to regret,that flummox you, unimaginable things that make youpause and reconsider who you really are, what you arecapable of.Karen Brown, “The Philter,” Little Sinners and Other Stories, 2012

Origin

Flummox arose in the early 1800s; its origin isunknown.

Source: flummox – Word of the Day | Dictionary.com