appall (v.) Look up appall at Dictionary.com
also appal, early 14c., "to fade;" c.1400, "to grow pale," from Old French apalir "become or make pale," from a- "to" (see ad-) + palir "grow pale," from Latin pallere (see pallor). Meaning "cause dismay or shock," is 1530s. Related: Appalled; appalling.