The most common and most likely answer to this crossword clue is the 5 letter word CRUDE
I've seen this crossword clue in Financial Times
C
R
U
D
E
More clues leading to the result CRUDE
- Oil? Carful does, regularly
- Initially coarse and unrefined?
- Charlie’s discourteous and rough
- Waste matter and energy, lacking refinement
- Charlie argued regularly with environmentalists’ leader, becoming vulgar
- Without or without a spot of custard on the side it’s tasteless
- Oil company’s head dispensing with courtesy
- Vulgar when backing out of expedition
- A bit crass and vulgar
- Primarily crass and vulgar
Buddy explains!

The straight part
We know that "lacking refinement" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lacking refinement = crude.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 CRUDE mean?
CRUDE noun- Any substance in its natural state.
- Crude oil.
- In a natural, untreated state.
- Characterized by simplicity, especially something not carefully or expertly made.
- Lacking concealing elements.
- Lacking tact or taste.
- Immature or unripe.
- (grammar) Pertaining to the uninflected stem of a word.