The most common and most likely answer to this crossword clue is the 6 letter word NUGGET
I've seen this crossword clue in The Guardian
N
U
G
G
E
T
More clues leading to the result NUGGET
- Having brought up weapon, secure a lump of gold
- Weapon returned to obtain some gold, perhaps
- Turning arm, see lump
- Raised pistol to catch something small but valuable
- Fanatic collecting what’s laid up in lump
- Understand after weapon turned up — valuable little piece
- Food — food churning over inside — something lumpy
- Colt perhaps backed to achieve gold
- Shooter making comeback, striking left side of target — it’s gold!
- Heading west, shooter needs to grab some gold
Buddy explains!

The straight part
We know that "lump" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lump = nugget.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 NUGGET mean?
NUGGET noun- A small, compact chunk or clump.
- A chicken nugget.
- A tidbit of something valuable.
- A small piece of tasty food, a tidbit.
- A type of boot polish.
- A bud from the Cannabis sativa plant, especially one that is potent.
- An inexperienced, newly trained fighter pilot.
- A partial description gleaned from data mining.