The most common and most likely answer to this crossword clue is the 5 letter word AGENT
I've seen this crossword clue in The Times
A
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More clues leading to the result AGENT
Buddy explains!
The straight part
We know that "Spy" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case spy = agent.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 AGENT mean?
AGENT noun- One who exerts power, or has the power to act
- One who acts for, or in the place of, another (the principal), by authority from him/her; someone entrusted to do the business of another
- A person who looks for work for another person
- Someone who works for an intelligence agency
- An active power or cause or substance; something which has the power to produce an effect
- In the client-server model, the part of the system that performs information preparation and exchange on behalf of a client or server. Especially in the phrase “intelligent agent” it implies some kind of autonomous process which can communicate with other agents to perform some collective task on behalf of one or more humans.
- (grammar) The participant of a situation that carries out the action in this situation, e.g. "the boy" in the sentences "The boy kicked the ball" and "The ball was kicked by the boy".
- A cheat who is assisted by dishonest casino staff.