Most inferior variety of towels (6)
I believe the answer is:
'most inferior' is the definition.
('low' can be similar in meaning to 'inferior')
'variety of towels' is the wordplay.
'variety of' indicates an anagram.
'towels' with letters rearranged gives 'LOWEST'.
(Other definitions for lowest that I've seen before include "Towels for the most humble" , "very close to the ground" , "Smallest number" , "extremely vulgar" , "Least high" .)