One well-upholstered sofa ripped around end of armrest (5)
I believe the answer is:
fatso
'one well-upholstered' is the definition.
I can't judge whether this definition defines the answer.
'sofa ripped around end of armrest' is the wordplay.
'ripped' indicates an anagram (letters ripped or torn up).
'around' indicates putting letters inside.
'end of' suggests the final letters.
The last letter of 'armrest' is 't'.
'sofa' anagrammed gives 'faso'.
'faso' going around 't' is 'FATSO'.
Can you help me to learn more?
(Other definitions for fatso that I've seen before include "Derogatory term for an overweight person" , "Plump person" , "Great lump" .)