The term 'shake up' can be defined as a sudden and dramatic change or disruption. The crossword solutions for this term include SPOOK (5 letters), UNHINGE (7 letters), JAR (3 letters), FAZE (4 letters), JOLT (4 letters), ROCK (4 letters), ROIL (4 letters), ADDLE (5 letters), ROUSE (5 letters), SCARE (5 letters), REMOVE (6 letters), AGITATE (7 letters), DISRUPT (7 letters), STARTLE (7 letters), UNNERVE (7 letters), TURNOVER (8 letters), UNSETTLE (8 letters), and UNBALANCE (9 letters). Each of these words can be used to describe a shake up, as they all involve a sudden and dramatic change or disruption.