personality disorder

NOUN /,pɜrsə'nælɪti_dɪs'ɔrdər/
20 LETTERS · 7 SYLLABLES · STARTS WITH P

personality disorder is a valid 20-letter word worth 26 points in Scrabble and 28 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
P3E1R1S1O1N1A1L1I1T1Y4D2I1S1O1R1D2E1R1
3 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 4 + 0 + 2 + 1 + 1 + 1 + 1 + 2 + 1 + 1 =26 PTS
DOUBLE WORD → 52TRIPLE WORD → 78
MEANING

What does personality disorder mean?