Tentative approaches made to test attitudes or gather information, or the sensory appendages of insects and other creatures.
From 'feel' plus agent suffix '-er'. Extended metaphorically from insect antennae to human behavior by the 1800s, capturing how both insects and people use delicate probing to understand their environment.
The metaphorical leap from insect antennae to diplomatic or social probing is brilliant - both involve careful, tentative touching to gather crucial information about the environment. Politicians and insects both succeed by knowing when to extend their feelers and when to pull them back.
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