A person or thing that deprives someone of something.
From deprive + -er (agent suffix indicating someone who performs an action). This standard English formation directly parallels words like 'teacher' (teach + -er).
Depriver is grammatically sound and uses the most common English way to make agent nouns (-er), yet it's not a word you'll find in many dictionaries—English reserves this term for rare, formal contexts rather than everyday speech.
Complete word intelligence in one call. Free tier — 50 lookups/day.