feeler

noun

1.
one of a pair of mobile appendages on the head of e.g. insects and crustaceans; typically sensitive to touch and taste
feelers sailyard antenna
Derived from:
feel
2.
a tentative suggestion designed to elicit the reactions of others
advance approach overture
3.
sensitivity similar to that of a receptor organ
antenna
4.
slender tactile process on the jaws of a fish
barbel
Derived from:
feel