You'll never get much gratitude from one (3)
I believe the answer is:
rat
'one' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'you'll never get much gratitude' is the wordplay.
'you'll never' becomes 'ra' (I am not sure about this - if you are sure you should believe this answer much more).
'get' means one lot of letters go next to another.
'much' means to remove the last letter (much but not all of the word).
'gratitude' becomes 'ta' (I've seen this in other clues).
'ta' with its final letter taken away is 't'.
'ra'+'t'='RAT'
'from' acts as a link.
Can you help me to learn more?
(Other definitions for rat that I've seen before include "one who deserts the sinking ship?" , "Treacherous person" , "Sewer rodent" , "that gets out of stricken vessel" , "Unpleasant character" .)