The term 'step up' can be defined as to INCREASE or improve, and the crossword solutions for this term include 'HURRY' (5 letters), 'REV' (3 letters), 'HASTEN' (6 letters), 'amp' (3 letters), 'RUNG' (4 letters), 'STAIR' (5 letters), 'AUGMENT' (7 letters), 'ESCALATE' (8 letters), 'INCREASE' (8 letters), 'PROMOTION' (9 letters), 'ACCELERATE' (10 letters), 'AMELIORATE' (10 letters), 'ESCALATION' (10 letters), and 'faceachallenge' (14 letters). These words all suggest taking action to improve or INCREASE something, whether it be quickly or gradually.