Indefatigablenesses is valid word

Is indefatigablenesses a scrabble word?
Official Scrabble Players Dictionary NO
Official Tournament and Club Word List NO
Collins Scrabble Words NO
Is indefatigablenesses valid Words with Friends?
Words with Friends NO

Definitions for INDEFATIGABLENESSES in dictionary:

Find what other words can be done using letters: "indefatigablenesses"
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