Fat ten not to be seen (5)
I believe the answer is:
obese
'fat' is the definition.
(similar in meaning)
'ten not to be seen' is the wordplay.
'OBESE' is hidden in amongst the letters.
But, I'm unsure how this is indicated.
Can you help me to learn more?
(Other definitions for obese that I've seen before include "Extremely fat" , "Grossly overweight" , "indecently large)" , "Morbidly fat" , "Extremely overweight" .)