longstanding

[ lawng-stan-ding, long- ]
/ ˈlɔŋˈstæn dɪŋ, ˈlɒŋ- /

adjective

existing or occurring for a long time: a longstanding feud.

Origin of longstanding

First recorded in 1595–1605; long1 + standing
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for longstanding