Synonyms for Feeler (same or very similar meaning)
WordNet sense 1 (a tentative suggestion designed to elicit the reactions of others):
advance, approach, overtureWordNet sense 2 (sensitivity similar to that of a receptor organ):
antennaWordNet sense 3 (slender tactile process on the jaws of a fish):
barbelFrom the ODE community, based on WordNetadd/edit