long-standing Synonyms

longstanding well-established substantial strong stout steady steadfast staying stationary stable sound settled protracted sustained traditional unfluctuating long-established dyed-in-the-wool confirmed stabile unyielding long-term long-lasting Antiguan older unalterable prolonged persistent firm FAST established enduring durable diuturnal continuing constant consistent chronic ancient former immemorial incurable perpetual permanent perennial perdurable old-fashioned long-lived long lingering