The term 'not careful' can be described by a variety of words, all of which have been used as solutions to a crossword puzzle. These words include 'RASH' (4 letters), 'LAX' (3 letters), 'UNWARY' (6 letters), 'REMISS' (6 letters), 'UNCOUTH' (7 letters), 'SLAPDASH' (8 letters), 'UNGUARDED' (9 letters), and 'IMPROVIDENT' (11 letters). All of these words imply a lack of caution or thoughtfulness, and can be used to describe someone who is not careful in their actions.