WordWeb Online

1. Filled with bewilderment
   - at a loss, nonplused, puzzled

1. Be confusing or perplexing to; cause to be unable to think clearly
   "These questions nonplus even the experts";
   - confuse, throw, fox, befuddle, fuddle, bedevil, confound, discombobulate, perplex, vex, stick, get, puzzle, mystify, baffle, beat, pose, bewilder, flummox, stupefy, gravel, dumbfound

See also: perplexed

Type of: be

Encyclopedia: Nonplussed