The word "in firmest" is spelled as /ɪn ˈfɜrməst/. The first syllable is pronounced as the short 'ih' sound, followed by the stressed syllable with the 'er' sound. The ending is pronounced with the 'm' sound followed by a 'st' cluster. This word is the superlative form of the adjective 'infirm', meaning weak or lacking in strength. "In firmest" refers to the weakest or most vulnerable state of something. Proper spelling is important for effective communication and avoiding misunderstandings.