Third person singular present tense of 'golf'; plays the sport of golf, or hits a golf ball.
From 'golf,' with the regular third-person singular present inflection '-s' added. 'Golf' as a verb became standard in the 19th century as the sport gained popularity.
English speakers took the noun 'golf' and verbed it easily—'he golfs' sounds natural to us now, but this kind of noun-to-verb transformation was more productive in the Victorian era when golf was still novel.
Complete word intelligence in one call. Free tier — 50 lookups/day.