The spelling of the word "haddest fitting" may appear confusing to some, but it is simply the past tense form of the verb "to have," "had," in combination with the superlative adjective "fitting," meaning most suitable. The pronunciation is /ˈhædɪst ˈfɪtɪŋ/. The suffix "-est" is added to the end of "had" to indicate the superlative, making it "haddest." When combined with "fitting," the final result is "haddest fitting," which means the most suitable thing that has been had in the past.