lengthy vs protracted

lengthy and protracted both are adjectives.

Word	Noun	Adjective	Verb	Adverb
lengthy	No	Yes	No	No
protracted	No	Yes	No	No

As adjectives, lengthy and protracted are synonyms defined as:

lengthy and protracted: relatively long in duration; tediously protracted

Other synonyms of lengthy include drawn-out, extended, prolonged.

lengthy (adjective)	protracted (adjective)
relatively long in duration; tediously protracted	relatively long in duration; tediously protracted