feeler

n. 1. One who, or that which, feels. [ 1913 Webster ]

2. (Zool.) 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. [ 1913 Webster ]

Insects . . . perpetually feeling and searching before them with their feelers or antennæ. Derham. [ 1913 Webster ]

3. Anything, as a proposal, observation, etc., put forth or thrown out in order to ascertain the views of others; something tentative. [ 1913 Webster ]