'pleaser' is formed in English from the verb 'please' + agentive suffix '-er'. 'Please' originates from Old French 'plaisir' (or Medieval French 'plaisir'), ultimately from Latin 'placēre', where 'plac-' meant 'to please' or 'to be acceptable'.

'please' came into Middle English from Old French (plaisir / pleseir) and Latin 'placēre'; the agent noun form (verb + -er) produced 'pleaser' in Modern English to mean 'one who pleases'.

Initially derived to mean 'one who pleases' (agent of 'please'), and this core sense has remained stable; extended senses (e.g., a 'pleasing thing' or 'crowd-pleaser') developed later.