Correct spelling for the English word "suitest" is [sˈuːtəst], [sˈuːtəst], [s_ˈuː_t_ə_s_t] (IPA phonetic alphabet).
The word "suitest" is a combination of the words "suite" and "est". "Suite" comes from the French word "suite", meaning "a series" or "a sequence". It also originally referred to a set of connected rooms in buildings. "Est" is a suffix used to form the superlative degree of adjectives in English, meaning "most" or "highest". Hence, "suitest" is a playful portmanteau or wordplay, created to emphasize that something is the utmost or highest example of a suite.