Inextensibility is valid Scrabble Word

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

Definitions for INEXTENSIBILITY in dictionary:

Similar words containing EXTENSIBIL without suffix ity and without prefix in

extensibility25 extensibilities24
Find what other words can be done using letters: "inextensibility"
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