Drawn-out and Longest

Drawn-out adjective - Relatively long in duration; tediously protracted.

Longest and drawn-out are semantically related In some cases you can replace term "Longest" with "Drawn-out", this terms are similar.

Longest adverb - For the most time.

Drawn-out and longest are semantically related in interminable topic. Sometimes you can use "Drawn-out" instead an adjective "Longest".