The spelling of the word "showest" can be a bit confusing. In IPA phonetic transcription, it is pronounced as /ˈʃoʊəst/, with the stress on the first syllable. The "oe" combination in the middle of the word is a diphthong that sounds like the "o" in "go" and the "e" in "me". The "-est" suffix at the end is used to form the second person singular present tense of the verb "show". Therefore, "showest" means "you show" in an old-fashioned or poetic way.
The word "showest" is derived from the Old English word "sceawian" meaning "to look at, behold, or show". In Middle English, the word evolved to "schewe" or "shewen", eventually leading to the modern English verb "show". "Showest" is the second person singular form of the verb "show" in the present tense and is typically used when addressing a single person.