Sentence:  Five High School boys came down the road abreast. Ellis saw them coming, a row of yellow, malicious faces—<WSD>epicene</WSD> faces, horribly smooth and young, grinning at him with deliberate insolence. 
Meaning of the word marked with <WSD> tags:  Of indeterminate sex, whether asexual, androgynous, hermaphrodite, or intersex; of a human face, intermediate in form between a man's face and a woman's face.