mix_up
1. [ verb ] assemble without order or sense
Synonyms: confuse jumble
Examples:

"She jumbles the words when she is supposed to write a sentence"

Related terms: assemble addle mistake patchwork
2. [ verb ] cause to be perplexed or confounded
Synonyms: stump
Examples:

"This problem stumped her"

Related terms: perplex poser
Similar spelling:   mix-up