(spies, ~ing, spied)
1.
A ~ is a person whose job is to find out secret information about another country or organization.
He was jailed for five years as an alleged British ~...
N-COUNT
2.
A ~ satellite or ~ plane obtains secret information about another country by taking photographs from the sky.
ADJ: ADJ n
3.
Someone who spies for a country or organization tries to find out secret information about another country or organization.
The agent spied for East Germany for more than twenty years...
East and West are still ~ing on one another...
I never agreed to ~ against the United States.
VERB: V for n, V on n, V against n
~ing
...a ten-year sentence for ~ing.
N-UNCOUNT
4.
If you ~ on someone, you watch them secretly.
That day he spied on her while pretending to work on the shrubs...
VERB: V on n
5.
If you ~ someone or something, you notice them. (LITERARY)
He was walking down the street when he spied an old friend.
= spot
VERB: V n