lengthy vs extended

lengthy and extended both are adjectives.

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

As adjectives, lengthy and extended are synonyms defined as:

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

lengthy (adjective)	extended (adjective)
relatively long in duration; tediously protracted	fully extended or stretched forth
	beyond the literal or primary sense
	large in spatial extent or range or scope or quantity
	drawn out or made longer spatially
	relatively long in duration; tediously protracted