Sentence:  Greenberger and Steinberg coined the term “<WSD>adultoid</WSD>” to describe adolescents who engage in activities, often “risky” activities, that symbolize adult status (e.g., smoking, drinking, staying out late, having sex). 
Meaning of the word marked with <WSD> tags:  An (adolescent) who engages in activities that symbolize (adult) (status).