One who forces or compels; a person or thing that applies force or coercion.
From force + -er (Old English -ere, agent suffix). The -er suffix creates nouns from verbs, naming the agent or person who performs the action.
The -er suffix is English's most productive way to name people by their actions: teach → teacher, run → runner, force → forcer. It's so natural that 'forcer' feels like it *should* exist, even though we more commonly use 'coercer' or just say 'someone who forces things.'
Complete word intelligence in one call. Free tier — 50 lookups/day.