Had spied five entering in the early morning (4)
I believe the answer is:
seen
'had' is the definition.
The answer and definition can be both to do with communicating as well as being past participle verbs.
Perhaps you can see an association between them that I don't see?
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for seen that I've seen before include "Perceived by sight" , "Met - understood" , "Viewed" , "Spotted" , "Observed or percieved" .)