The term COMPLETELY MISTAKEN can be represented by three different crossword solutions: OUTINTFELFIELD (14 letters), DEADWRONG (9 letters), and OUTINLEFTFIELD (14 letters). All three of these solutions refer to the same concept, that of being completely wrong or mistaken. The phrase 'out in left field' is an idiom which means to be completely off base or incorrect in one's thinking. Similarly, 'dead wrong' is another idiom which means to be completely wrong. The phrase 'out in T-field' is a variation on the phrase 'out in left field', with the letter T standing in for the word left.