The most common and most likely answer to this crossword clue is the 7 letter word PITPROP
I've seen this crossword clue in The Daily Telegraph
P
I
T
P
R
O
P
More clues leading to the result PITPROP
- Support for underground workers
- Support, way down the bed, one hugging hooker?
- Time for Philip to protect supporter of mine
- A supporter of mine gets shot crossing river
- Bed, and public relations work for a supporter of mine!
- Supporter of India invested in some tax-exempt properties
- One holds up underground service, overturning publicity operation
- A supporter of mine?
Buddy explains!
The straight part
We know that "One holds up underground" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one holds up underground = pitprop.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.