rigorousness

NOUN
12 LETTERS · STARTS WITH R

rigorousness is a valid 12-letter word worth 13 points in Scrabble and 16 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
R1I1G2O1R1O1U1S1N1E1S1S1
1 + 1 + 2 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 =13 PTS
DOUBLE WORD → 26TRIPLE WORD → 39
MEANING

What does rigorousness mean?