The most common and most likely answer to this crossword clue is the 5 plus 3 letter word DRILL BIT
I've seen this crossword clue in The Sunday Telegraph
D
R
I
L
L
B
I
T
More clues leading to the result DRILL BIT
- Boring part of school had an impact
- Training started to work for one with speed on the turn
- Exercise component, boring thing
- Training on little part for tool
- Train snapped — that’s the boring part
- Exercise little — it can be boring
- Part of routine that can be a bore?
- Sick have small portion under doctor — it might well be boring
Buddy explains!
The straight part
We know that "boring thing" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case boring thing = drill bit.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.