The most common and most likely answer to this crossword clue is the 6 letter word BUNKER
I've seen this crossword clue in Financial Times
B
U
N
K
E
R
More clues leading to the result BUNKER
Buddy explains!
The straight part
We know that "Underground shelter/for trapped clubmen" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case underground shelter/for trapped clubmen = bunker.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 BUNKER mean?
BUNKER noun- A hardened shelter, often buried partly or fully underground, designed to protect the inhabitants from falling bombs or other attacks.
- A large container or bin for storing coal, often built outside in the yard of a house. Now rare, as different types of fuels and energy sources are being used.
- A container for storing coal or fuel oil for a ship's engine. [Also, by extension] the quantity of fuel needed to replenish that container.
- The coal compartment on a tank engine.
- A sand-filled hollow on a golf course.
- An obstacle used to block an opposing player's view and field of fire.
- A sort of chest or box, as in a window, the lid of which serves for a seat.
- A kitchen worktop.
- One who bunks off; a truant from school.
- Certain fish, menhaden.
- To load a vessel with oil or coal for the engine.
- To hit a golf ball into a bunker.
- To fire constantly at a hiding opponent, preventing them from firing at other players and trapping them behind the barrier. This can also refer to eliminating an opponent behind cover by rushing the position and firing at extremely close range as the player becomes exposed.