The most common and most likely answer to this crossword clue is the 7 letter word POLITIC
I've seen this crossword clue in The Daily Telegraph
P
O
L
I
T
I
C
More clues leading to the result POLITIC
- Statesman-like, still keeping Oscar fired up
- Diplomatic force almost smothers it
- Wise of boys in blue briefly to secure city centre
- It could be expedient if most of 21 down steal one time
- Discreet love illuminated in film
- Reduced force used to seize it? That’s prudent
- Sagacious, well-mannered for the most part and in charge
- Shrewd officers nearly seizing computers etc
Buddy explains!

The straight part
We know that "Sagacious" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sagacious = politic.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 POLITIC mean?
POLITIC noun- A politician.
- To engage in political activity; politick.
- Of or relating to polity, or civil government; political.
- (of things) Relating to, or promoting, a policy, especially a national policy; well-devised; adapted to its end, whether right or wrong.
- Sagacious in promoting a policy; ingenious in devising and advancing a system of management; devoted to a scheme or system rather than to a principle; hence, in a good sense, wise; prudent; sagacious
- Shrewd, prudent and expedient.
- Discreet and diplomatic.
- Artful, crafty or cunning.