The most common and most likely answer to this crossword clue is the 6 letter word BETOOK
I've seen this crossword clue in The Guardian
B
E
T
O
O
K
Buddy explains!
The straight part
We know that "Applied" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case applied = betook.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 BETOOK mean?
BETOOK verb- To beteach.
- To take over to; take across (to); deliver.
- To seize; lay hold of; take.
- To take oneself to; go or move; repair; resort; have recourse.
- To commit to a specified action.
- To commend or entrust to; to commit to.
- To take oneself.