veteran
n. countablen. someone who has a lot of experience in a specific job or activity, especially someone who served in the military. You use this to show respect for their long service or deep knowledge.
n. a person who has had long experience in a particular field; specifically, a former member of the armed forces. Often used as a modifier before another noun to indicate seasoned expertise.
The old soldier is a veteran of the second world war.
As a veteran of the publishing industry, she knew exactly which editors would be interested in the new manuscript.
The political veteran navigated the complex negotiations with a level of calm that only comes from decades of experience in high-stakes diplomacy.
Borrowed from Middle French vétéran, from Latin veterānus.
Commonly followed by the preposition 'of' to specify the field of experience.