The term 'extreme' can be defined as the highest degree or intensity of something. The crossword solutions for this term include 'STERN' (5 letters), 'TOO' (3 letters), 'RANK' (4 letters), 'EXTRA' (5 letters), 'DEEP' (4 letters), 'END' (3 letters), 'FAR' (3 letters), 'NTH' (3 letters), 'DIRE' (4 letters), 'LAST' (4 letters), 'RASH' (4 letters), 'OUTER' (5 letters), 'RABID' (5 letters), 'ULTRA' (5 letters), 'UNDUE' (5 letters), 'UTTER' (5 letters), 'ARRANT' (6 letters), 'FRINGE' (6 letters), 'HEIGHT' (6 letters), 'SEVERE' (6 letters), 'tootoo' (6 letters), 'UTMOST' (6 letters), 'DRASTIC' (7 letters), 'INTENSE' (7 letters), 'RADICAL' (7 letters), 'DESPERATE' (9 letters), 'UTTERMOST' (9 letters), and 'INORDINATE' (10 letters). These words all describe something that is at the highest level of intensity, from 'STERN' which means very strict, to 'INORDINATE' which means excessive or beyond what is normal.