He put out some feelers during the meeting to test everyone's reactions.

feelers 是名词，来自动词 feel（感觉）加后缀 -er 构成，原指昆虫的"触角"，比喻为"试探性言行"。 put out feelers 是固定短语，字面意思是"伸出触角"，比喻为"试探性地了解情况"。