Go through (9)
'go through' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for penetrate that I've seen before include "Pass into or through" , "Pierce" , "Go through" , "Run through" , "Force way through, into" .)
'go through' is the definition.
(experiencing is a kind of going through)
This is the entire clue.
(Other definitions for experience that I've seen before include "Undergo" , "Try" , "what Hendrix had" , "Participate in - knowledge and understanding gained" , "What one has been through and is supposed to learn from" .)