feeler

(noun) one of a pair of mobile appendages on the head of e.g. insects and crustaceans; typically sensitive to touch and taste. Synonyms: antenna.

(noun) a tentative suggestion designed to elicit the reactions of others. Synonyms: overture, advance, approach. Example: "She rejected his advances."

(noun) sensitivity similar to that of a receptor organ. Synonyms: antenna. Example: "He had a special antenna for public relations."

(noun) slender tactile process on the jaws of a fish. Synonyms: barbel.