Sentence:  The nation was a mess environmentally, and only a few <WSD>voices in the wilderness</WSD> were paying heed. In 1970, environmentalists often were derided and dismissed. 
Meaning of the word marked with <WSD> tags:  A person, publication, or other source of assertions that expresses an opinion, doctrine, or point of view which is ignored or rejected by almost all others; the actual utterance of an unpopular opinion, doctrine, or point of view.