... 'Pants on!', instructed lawyer (7)

I believe the answer is:

briefed

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'instructed lawyer' is the definition.
'briefed' can be an answer for 'instructed' (briefing is a kind of instructing). I'm not sure about the 'lawyer' bit.

I don't understand the rest of the clue.

Can you help me to learn more?

(Other definitions for briefed that I've seen before include "Informed of the facts" , "Advised or instructed, like barrister" , "Prepared" , "Instructed in advance" .)

I've seen this clue in The Telegraph.

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