Terribly poor American is absorbent (6)
I believe the answer is:
porous
'absorbent' is the definition.
Both the definition and answer are adjectives. Perhaps you can see a link between them that I can't see?
'terribly poor american' is the wordplay.
'terribly' is an anagram indicator.
'american' becomes 'US' (United States).
'poor' with letters rearranged gives 'poro'.
'poro'+'us'='POROUS'
'is' is the link.
Can you help me to learn more?
(Other definitions for porous that I've seen before include "Pitted with little holes, like skin" , "Allowing liquid or gas to pass" , "Able to absorb fluids" , "Like a leaky field" , "Pitted with small holes like skin" .)