In a state of being checked, stopped, or held back; at a standstill or under control.
From the prefix 'a-' (in, at, or on) combined with 'check' (to stop or verify), forming a phrase meaning 'in a checked state', used in older English literature.
The phrase 'acheck' appears in Shakespeare and medieval texts to describe horses held back by reins or situations kept under control—it's a frozen moment in language history of how adverbs were formed differently.
Complete word intelligence in one call. Free tier — 50 lookups/day.