Badly in need of medical care (3)

I believe the answer is:

ill

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'badly' is the definition.
('ill' can be adverbial as in 'ill-advised')

I don't understand the remainder of the clue.

(Other definitions for ill that I've seen before include "Unwell from bacillus" , "Infirm" , "Off colour?" , "Shakespeare: '. . . met by moonlight'" , "Indisposed" .)

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

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