IPA: /ˈtræfɪkər/
KK: /ˈtræfɪkər/
A person who illegally trades or deals in something, often referring to drugs or people.
The police arrested a trafficker who was smuggling drugs across the border.
Trafficker → It is formed from "traffic" (from Old French *trafic*, meaning trade or commerce) and "-er" (meaning a person who). A trafficker is a person involved in trade or commerce, often with a negative connotation related to illegal activities.
Think of someone who is involved in 'trade' ('traffic') — the '-er' just means a person. A trafficker is someone who engages in trade, often in a questionable or illegal manner.