The term 'slip away' can be defined by the crossword solutions of VANISH (6 letters), FLY (3 letters), EVADE (5 letters), ESCAPE (6 letters), ELAPSE (6 letters), ERODE (5 letters), RUN (3 letters), and ELOPE (5 letters). To VANISH is to disappear suddenly, while to FLY is to move through the air using wings. To EVADE is to avoid or ESCAPE from something, while to ESCAPE is to get away from a place or situation. To ELAPSE is to pass slowly, while to ERODE is to gradually wear away. To RUN is to move quickly on foot, while to ELOPE is to RUN away secretly to get married.