Requiring or involving compulsion; mandatory, obligatory (rare variant of 'compulsory').
From Latin 'compellere' (compel) plus the suffix '-atory' (characterized by, relating to). This is a less common variant than 'compulsory' but follows standard Latin-derived adjective patterns.
English has two competing forms here—'compulsory' won out in most contexts, but 'compulsatory' persists in legal and formal writing, showing how language keeps old variants alive in specialized niches.
Complete word intelligence in one call. Free tier — 50 lookups/day.