Hit hard — huge letdown (6)
I believe the answer is:
bathos
'letdown' is the definition.
The definition and answer can be both feelings as well as being singular nouns.
Maybe there's a link between them I don't understand?
'hit hard huge' is the wordplay.
'hit' becomes 'bat' (batting is a kind of hitting).
'hard' becomes 'h' (abbreviation used in pencil classifications).
'huge' becomes 'os' (abbreviation for outsize).
'bat'+'h'+'os'='BATHOS'
Can you help me to learn more?
(Other definitions for bathos that I've seen before include "Trite anticlimax" , "Ludicrous descent from serious to trivial" , "Serious-to-trivial switch" , "Unintentional trivialisation of mood" , "Unintentional slip from serious to trivial mood" .)