From The Collaborative International Dictionary of English v.0.48:
Feeler \Feel"er\, 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.
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Insects . . . perpetually feeling and searching
before them with their feelers or antenn[ae].
--Derham.
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3. Anything, as a proposal, observation, etc., put forth or
thrown out in order to ascertain the views of others;
something tentative.
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