appal

The journey of 'appal' begins with the Latin adjective 'pallidus', meaning pale, which itself derives from the verb 'pallere', to be pale. This verb is of Proto-Indo-European origin, likely from a root meaning gray. The word entered Old French as 'apalir', meaning to grow or make pale. Adopted into Middle English, its meaning evolved from the physical reaction of turning pale from fear or shock to the more abstract emotional state of being horrified or deeply dismayed. Thus, the modern sense of causing shock and outrage retains the core logic of a visceral, physically manifesting reaction to a dreadful sight or idea.

The word 'appal' is a simplex word. It entered English as a whole unit from Old French 'apalir' meaning "to grow pale". Its ultimate origin is the Latin prefix 'ad-' (to, towards) and the Latin word 'pallidus' (pale).