'inviter' ultimately originates from Old French, specifically the word 'inviter', which in turn comes from Latin 'invitare' meaning 'to invite or entertain'.

'inviter' passed into English via Old French 'inviter'; the verb 'invite' entered Middle English from these sources, and the agent noun formed with English/French-derived suffix '-er' produced modern 'inviter'.

Initially it was associated with the Latin sense of 'entertain or summon'; over time the meaning narrowed to the modern sense of 'to ask someone to attend', and 'inviter' came to mean 'a person who invites'.