The most common and most likely answer to this crossword clue is the 7 letter word REEFERS
I've seen this crossword clue in The Guardian
R
E
E
F
E
R
S
More clues leading to the result REEFERS
- Alludes to boarding eastern midshipmen
- Double-breasted jackets originally exhibited in adverts
- Conserving energy, passes on the wacky baccy
- Visionary official involved in about-turn on cigarettes
- Jackets for midshipmen
- Sailors’ smokes
- They’re usually concealed in smoking jackets
- Errs badly about reversing charge for jackets
- Queen wears rocks and jackets
- 19 Relaxation — mostly drinks, free rummy and cigarettes
Buddy explains!

The straight part
We know that "wacky baccy" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case wacky baccy = reefers.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 REEFERS mean?
REEFERS noun- Someone who reefs sails, especially a midshipman.
- A reefer jacket; a close-fitting jacket or short coat of thick cloth.
- A refrigerated, insulated trailer, ship or shipping container.
- A refrigerator car (type of boxcar).
- A marijuana cigarette.
- Marijuana.