Was abusive yet guarded? (6)

I believe the answer is:

railed

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'guarded?' is the definition.
Although both the answer and definition are past participle verbs, I can't understand how they can define each other.

I don't understand the rest of the clue.

Can you help me to learn more?

(Other definitions for railed that I've seen before include "Redial (anag.)" , "Complained or protested strongly" , "Complained strongly, being fenced in" , "Protected by barred fencing" , "Complained angrily, being barred" .)

I've seen this clue in The Globe and Mail.

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