malignant tumor

NOUN /mə'lɪgnənt_'tumər/
15 LETTERS · STARTS WITH M

malignant tumor is a valid 15-letter word worth 19 points in Scrabble and 26 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
M3A1L1I1G2N1A1N1T1T1U1M3O1R1
3 + 1 + 1 + 1 + 2 + 1 + 1 + 1 + 1 + 0 + 1 + 1 + 3 + 1 + 1 =19 PTS
DOUBLE WORD → 38TRIPLE WORD → 57
MEANING

What does malignant tumor mean?