The answer is faugh.
It's five letters, ending in H. Faugh refers to the exclamation of contempt, disgust, or abhorrence.
Skoal
The letter 'O'
No, there should not be a capital letter after an exclamation mark. After an exclamation mark, you should start the next sentence with a lowercase letter unless it is a proper noun.
titled
loon
evolve
It could be a 'port'...
again
poll
omitted
Talc
Talk