A kink is anything outside conventional sex that someone enjoys. A fetish is narrower: a specific object, material or body part that someone needs, or strongly prefers, in order to be aroused. Every fetish is a kink. Most kinks are not fetishes.
The textbook difference
- Kink. An interest. You enjoy it, and sex without it still works. Someone who likes being tied up but is perfectly happy without rope has a kink.
- Fetish. A requirement, or close to one. Arousal depends on it, or is much weaker without it. Someone who needs feet involved to get there has a fetish.
The difference is necessity, not strangeness. A very mild interest you cannot do without is a fetish; a wild one you can take or leave is a kink.
Where it breaks down
In ordinary speech, almost completely. People use the words interchangeably, adverts use fetish as a catch all for anything unusual, and nobody is grading themselves against a definition. Fetish also has a clinical sense, fetishistic disorder, which requires distress or impairment and describes almost nobody who uses the word about themselves.
So the distinction is worth knowing and not worth correcting people over.
Which word to use when you ask
Neither, mostly. Say the thing. “Do you do foot worship” gets a clear answer; “are you kink friendly” gets a vague one, because it means something different to everybody who says it. The specific request is the one that can be answered honestly, and it saves a booking that would not have worked.
Where this shows up in adverts
Profiles list fetish as a service category covering a wide range, and the detail is in what is named underneath. Kink meaning covers the broader word, fetish and domination escorts covers the labels in adverts and what to settle first, and the glossary covers the rest of the shorthand.