The correct spelling of the word "un smoother" is actually "unsmoother." The prefix "un-" means not or the opposite of, while the suffix "-er" is used to form comparative adjectives. The root word here is "smoother," which is spelled with a double "o" because the "oo" sound is pronounced as /uː/ in IPA phonetic transcription, representing a long vowel sound. The prefix "un-" and the suffix "-er" are both pronounced as /ʌn/ and /ər/, respectively.