This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. Having existed or persisted for a long time: a longtime friend; a longtime resident of Detroit.

adj. Having endured for a long period of time.

adj. of long duration

"Cuomo said that he has unearthed what he calls a longtime Albany secret that quietly and drastically increases spending in a flawed budget process."

old   

new    short-term   

long-timer   

long-term    long-standing   

long-time    erstwhile    one-time    influential    lifelong    full-time    sometime    would-be    senior    staunch