Indebted blonde foolishly keeping the man up (8)
I believe the answer is:
beholden
'indebted' is the definition.
(thesaurus)
'blonde foolishly keeping the man up' is the wordplay.
'foolishly' indicates anagramming the letters.
'keeping' means one lot of letters goes inside another.
'the man' becomes 'he'.
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'he' reversed gives 'eh'.
'blonde' anagrammed gives 'bolden'.
'bolden' enclosing 'eh' is 'BEHOLDEN'.
(Other definitions for beholden that I've seen before include "Owing gratitude (to)" , "Obliged" , "Bound" , "Under an obligation" , "Owing thanks, indebted" .)