The most common and most likely answer to this crossword clue is the 7 letter word COACHES
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More clues leading to the result COACHES
Buddy explains!

The straight part
We know that "instructors" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case instructors = coaches.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 COACHES mean?
COACHES noun- A wheeled vehicle, generally drawn by horse power.
- A passenger car, either drawn by a locomotive or part of a multiple unit.
- (originally Oxford University slang) A trainer or instructor.
- A single-decked long-distance, or privately hired, bus.
- The forward part of the cabin space under the poop deck of a sailing ship; the fore-cabin under the quarter deck.
- (chiefly US) The part of a commercial passenger airplane or train reserved for those paying the lower standard fares; the economy section.
- To train.
- To instruct; to train.
- To study under a tutor.
- To travel in a coach (sometimes coach it).
- To convey in a coach.