'arouser' originates from English, specifically the word 'arouse' combined with the agentive suffix '-er'.

'arouse' was formed from the prefix 'a-' (on, to) + 'rouse' (from Middle English 'rousen', ultimately influenced by Old French 'rousser'); adding the agentive suffix '-er' produced 'arouser'.

Initially it meant 'one who wakes or stirs up' (literal waking or stirring); over time it broadened to its current senses of 'one or something that excites or stimulates (interest, emotion, sexual desire)'.