The most common and most likely answer to this crossword clue is the 12 letter word INCAPACITATE
I've seen this crossword clue in Independent
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More clues leading to the result INCAPACITATE
- Make weak old Peruvian head over most of a big town
- Worriedly anticipate bill coming in will scupper one
- Take power away from a captain – cite misbehaving
- Put out of action, worriedly anticipate bill coming in
- Agitatedly anticipate bill coming in will cripple one
- Take power from a captain and cite changes
- Immobilise one cover raised in Peru’s old national gallery
Buddy explains!

The straight part
We know that "Make weak" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case make weak = incapacitate.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does INCAPACITATE mean?
INCAPACITATE verb- To make someone or something incapable of doing something; to disable.
- To make someone ineligible; to disqualify.