One who deserves something; a person who has earned or is worthy of something.
From 'deserve' plus the '-er' suffix (one who does or is something). This agent noun describes a person in the position of meriting or being worthy of reward or punishment.
Though grammatically valid, 'deserver' sounds awkward—we'd usually say 'he deserves it' rather than 'he is a deserver of it.' Some '-er' formations stick (lover, fighter, helper), while others get rejected by English speakers' ears as clumsy, showing that grammar alone doesn't determine word survival.
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