'feeler' originates from English, specifically formed from the verb 'feel' + the agentive suffix '-er', where 'feel' comes from Old English 'fēlan' meaning 'to perceive by touch'.

'feel' changed from Old English 'fēlan' (and Middle English forms such as 'felen') and eventually became the modern English verb 'feel'; the noun 'feeler' was formed later by adding the productive agent suffix '-er' to create 'one that feels' or something that probes.

Initially 'feel' meant 'to perceive by touch'; over time its sense broadened to include emotional perception, and the derived noun 'feeler' developed senses such as a sensory appendage, a probing instrument, and a tentative inquiry.