1. longest - Adverb
2. Longest - Proper noun
for the most time
Source: WordNetThe longest journey is the journey inwards. Of him who has chosen his destiny, Who has started upon his quest for the source of his being. Dag Hammarskjöld
The best liar is he who makes the smallest amount of lying go the longest way. Samuel Butler (novelist)
I am" is reportedly the shortest sentence in the English language. Could it be that "I do" is the longest sentence? George Carlin
Whoever stays awake longest must blow out the candle. Italian Proverb
The inarticulate speak longest. Japanese Proverb
A creaking door hangs longest. Romanian Proverb