What is the meaning of Feeler?

Someone or something that feels.

An antenna or appendage used for feeling, especially on an insect.

Something ventured to test another's feelings, opinion, or position.

a presumptive person; someone who bases on gut feeling, such as assuming or imagining that something said or done, whether positive or negative, was for a person despite having no concrete confirmation but gut feeling, or someone who assumes one's affection is reciprocated, or indulges in one's own wishful thinking or flatters oneself

Source: wiktionary.org