Feeler
WordNet
noun
(1) One of a pair of mobile appendages on the head of e.g. insects and crustaceans; typically sensitive to touch and taste
(2) Slender tactile process on the jaws of a fish
(3) Sensitivity similar to that of a receptor organ
"He had a special antenna for public relations"
(4) A tentative suggestion designed to elicit the reactions of others
"She rejected his advances"