Feeler

Webster's Dictionary of the English Language

·noun One who, or that which, feels.

II. Feeler ·noun Anything, as a proposal, observation, ·etc., put forth or thrown out in order to ascertain the views of others; something tentative.

III. Feeler ·noun One of the sense organs or certain animals (as insects), which are used in testing objects by touch and in searching for food; an antenna; a palp.