The most common and most likely answer to this crossword clue is the 6 letter word SMOKER
I've seen this crossword clue in Financial Times
S
M
O
K
E
R
More clues leading to the result SMOKER
Buddy explains!
The straight part
We know that "one ignoring health warnings" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one ignoring health warnings = smoker.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SMOKER mean?
SMOKER noun- A person who smokes tobacco habitually.
- A smoking car on a train.
- An informal social gathering for men only, at which smoking tobacco is allowed.
- (Cambridge University) A social event featuring sketches, songs, etc., whether or not smoking is carried out.
- A vent in the deep ocean floor from which a plume of superheated seawater, rich in minerals, erupts.
- An illicit boxing match; see Wikipedia:Battle Royal (boxing).
- A device that releases smoke intended to distract bees; a bee smoker.
- A person or an apparatus that smokes food.
- A two-stroke engine.
- (by extension) Any vehicle with a two-stroke engine, especially a motorcycle, as opposed to a four-stroke motorcycle or stroker.
- A fastball.
- A kind of pornographic film produced clandestinely in the early to mid-20th century, typically short and without sound.