$1,000, slangily (4)
I believe the answer is:
thou
'$1000 slangily' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for thou that I've seen before include "Subject" , "Refers to the person addressed (archaic)" , "Old-fashioned pronoun" , "Archaic form of you" , "You (many years ago)" .)