means a person who has built a large enough online following that brands pay them to promote products, opinions, or lifestyles to their audience

from From 'influence,' which arrived in English in the 14th century from Old French and ultimately Latin 'influere' — 'to flow in' — originally an astrological term for an ethereal fluid that streamed from the stars to shape human fate. The agent noun 'influencer' existed for centuries meaning simply 'one who influences,' but its modern sense — the social-media professional — flowed in during the 2010s, as platforms turned the old celestial trickle into a monetizable stream.