Plural of apprehension; either anxious concerns or acts of understanding/grasping something.
From apprehension + -s plural suffix. Apprehension comes from Latin apprehensio (seizure, understanding). The word has carried both meanings since Latin times. Plural forms regularized in Middle English.
The fact that one word means both 'anxiety' and 'understanding' traces back to how Roman minds worked—seizure of an idea and seizure of a person were seen as structurally identical mental acts!
Complete word intelligence in one call. Free tier — 50 lookups/day.