Fat American's remarkable LP and BMI (5)
I believe the answer is:
blimp
'fat american's' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'remarkable lp and bmi' is the wordplay.
'remarkable' indicates an anagram.
'and' says to put letters next to each other.
'lp' put after 'bmi' is 'bmilp'.
'bmilp' anagrammed gives 'BLIMP'.
Can you help me to learn more?
(Other definitions for blimp that I've seen before include "aircraft" , "full of hot air?" , "Small barrage balloon" , "returns one pound to provost" , "Large inflatable" .)