The phrase 'not all there' is an idiom used to describe someone who is not mentally present or is acting in a confused or irrational manner. The crossword solutions for this phrase include INSANE (6 letters), LOOPY (5 letters), LOCO (4 letters), PARTIAL (7 letters), ABSENT (6 letters), INCOMPLETE (10 letters), DAFT (4 letters), GONE (4 letters), DOTTY (5 letters), LOONY (5 letters), ENROUTE (7 letters), TETCHED (7 letters), ABRIDGED (8 letters), DERANGED (8 letters), and NONCOMPOSMENTIS (15 letters). All of these words are synonyms for the phrase 'not all there' and can be used to describe someone who is not mentally present or is acting in a confused or irrational manner.