Scant capital in Santander bank (7)
I believe the answer is:
slender
'scant' is the definition.
(thesaurus)
'capital in santander bank' is the wordplay.
'capital in' suggests taking the first letters.
'bank' becomes 'lender'.
The first letter of 'santander' is 's'.
's'+'lender'='SLENDER'
(Other definitions for slender that I've seen before include "Fine" , "remote" , "Shakespearean character" , "Willowy" , "Lean" .)