feeler
/ˈfiːlə(r)/noun
1- an animal organ such as an antenna or palp that is used for testing things by touch or for searching for food触须, 触角。
1.1
- figurative a tentative proposal intended to ascertain someone's attitude or opinion〈喻〉试探性建议, 试探手段：
they were sufficiently depressed to put out peace feelers.
他们沮丧得不得不进行了和平试探。