The word Stifening is misspelled against Stiffening, a noun meaning "Act or process of making stiff."
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Stiffening has double "ff" is mispronounced as "f"
Remember double 'FF' in between the strings Sti & ening which should not be misspelled with single 'F'
Wrong Spelling: Sti-f-ening
Correct Spelling: Sti-ff-ening
Find more wrongly spelled words of Stiffening to spell it well.