Unreliable item transmitted to dock guard (3-3,5)

'unreliable' is the definition.
I don't know anything about this answer so I can't judge whether this works.

'item transmitted to dock guard' is the wordplay.
I cannot really see how this works, but
'item' could be 'two' (I've seen this before) and 'two' is found in the answer.
'dock' could be 'bob' (I've seen this in another clue) and 'bob' is located in the answer.
'guard' could be 'watch' (watch is a kind of guard) and 'watch' is present in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?