Mother, tense, rests somehow - on this? (8)
I believe the answer is:
mattress
'this?' is the definition.
The definition suggests a singular noun which matches the answer.
'mother tense rests somehow' is the wordplay.
'mother' becomes 'ma' (ma is a kind of mother).
'tense' becomes 't' (abbreviation used in many dictionaries).
'somehow' indicates an anagram.
'rests' with letters rearranged gives 'tress'.
'ma'+'t'+'tress'='MATTRESS'
'on' acts as a link.
Can you help me to learn more?
(Other definitions for mattress that I've seen before include "Padded bag on which to sleep" , "Flat sleeping pad" , "Palliasse" , "Smartest kind of bed-base" , "Pad to sleep on" .)