WordWeb Online

1. A mistake that results from taking one thing to be another
   "he changed his name in order to avoid mix-up with the notorious outlaw"
   - confusion

1. Assemble without order or sense
   "She mixes up the words when she is supposed to write a sentence"
   - jumble, confuse
    
2. Cause to be perplexed or confounded
   - stump

Derived forms: mixes up, mixed up, mix-ups, mixing up

See also: mix

Type of: amaze, assemble, baffle, beat, bewilder, dumbfound, error, fault, flummox, get, gravel, mistake, mystify, nonplus, perplex, piece, pose, put together, puzzle, set up, stick, stupefy, tack, tack together, vex