The most common and most likely answer to this crossword clue is the 6 letter word CLEVER
I've seen this crossword clue in The Times
C
L
E
V
E
R
More clues leading to the result CLEVER
- Shrewd king attached to fourth wife’s place briefly
- First and third of colours always bright
- Smart Conservative crank?
- Capable Conservative means to apply pressure?
- Ingenious key comes with operating handle
- Extremely cheerful and always bright
- Able to go through without a hint of resistance
- Sharp cleaver clearing area
- Charlie’s bar? It’s bright!
- Conservative Party makes U-turn, being smart
Buddy explains!

The straight part
We know that "Capable" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case capable = clever.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 CLEVER mean?
CLEVER adjective- Nimble with hands or body; skillful; adept.
- Resourceful, sometimes to the point of cunning.
- Smart, intelligent, or witty; mentally quick or sharp.
- Showing inventiveness or originality; witty.
- (of an Aboriginal Australian) Possessing magical abilities.
- Fit; suitable; having propriety.
- Well-shaped; handsome.
- Good-natured; obliging.
- Fit and healthy; free from fatigue or illness.