Had been crying, one quickly saw (6)
I believe the answer is:
peeped
'had' is the definition.
The answer and definition can be both to do with perception as well as being past participle verbs.
Perhaps they are linked in a way I don't understand?
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for peeped that I've seen before include "Looked furtively at, like a certain Tom" , "Looked surreptitiously, maybe through keyhole" , "Looked covertly" .)