Sentence:  Rejuvenation was associated with a reinvigorated sex drive, and this connection generated an anxiety expressed in the <WSD>Faustian bargain</WSD>: damnation for a few extra years of carnal pleasure. 
Meaning of the word marked with <WSD> tags:  An agreement in which a person abandons his or her spiritual values or moral principles in order to obtain knowledge, wealth or other benefits.