The most common and most likely answer to this crossword clue is the 3 plus 4 letter word OIL WELL
I've seen this crossword clue in The Times
O
I
L
W
E
L
L
More clues leading to the result OIL WELL
- Maintenance advice for metal hinges in crude container
- Natural source of wealth: how to stop it seizing up?
- Painting efficiently's a boring source of income?
- Boring instructions to stop something squeaking?
- It supplies crude painting effectively
- Bore with instructions to mechanic?
- I might get boring here: do this to your bicycle chain
- Boring source of energy?
- One left to plug author, right away one’s bored
- Craftily lie low at length building source of riches
Buddy explains!
The straight part
We know that "boring source of income?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case boring source of income? = oil well.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.