Synonyms for Lengthy:

adj.

durable (adjective)
incessant, prolonged, lasting, long-life, perennial, durable, interminable, long, lifelong, everlasting, eternal, lifetime, livelong, perpetual, enduring.
extended (adjective)
interminable, drawn-out, windy, wordy, Overlong, prolonged, long-winded, dragging, elongate, long, verbose, protracted.
long (adjective)
protracted, long-drawn-out, drawn-out.
talkative (adjective)
wordy.
wordy (adjective)
grandiloquent, bombastic, chatty, rambling, talkative, wordy, loquacious, endless, excessive, superfluous, wandering, windy, featherbedding, ponderous, long-winded, verbose.

n.

forever, lingering, persistent, day in day out. elongate. excite, Overlong, long-drawn-out, dragging. lengthy (noun)
extended, long, drawn-out, protracted, prolonged.
prolix (noun)
dull, not brief.

Other synonyms:

Overlong, long-drawn-out, lingering. forever, persistent, dragging. Other relevant words:
drawn-out, dragging, extended, lingering, Overlong, long-drawn-out, elongate, protracted, persistent, dull.

Usage examples for lengthy

  1. This place of his is not prepared for a lengthy or luxurious residence; but as I have said, there is a house. – It Happened in Egypt by C. N. Williamson A. M. Williamson
  2. The argument with the rider was a lengthy one. – Audrey by Mary Johnston
  3. If exceptions to any ruling of the court are to be made the basis of proceedings in error, they must be carefully noted at the time, and afterwards made the subject of a lengthy set of papers. – The American Judiciary by Simeon E. Baldwin, LLD