What's the adjective for lengthinesses? Here's the word you're looking for.
Included below are past participle and present participle forms for the
verbs length and lengthen which may be used as adjectives within certain contexts.
“The valley wall itself was far too steep to climb, but it would be scalable to a man with a lengthy rope.”
“As we all know, we have already had a number of lengthy consultations about the new hospital.”
“On one occasion, Walker delivered a lengthy speech against a bill whose passage by the United States House of Representatives was a foregone conclusion.”