It sounds the same with the end cut off (3)
I believe the answer is:
hah
'it sounds the same' is the definition.
The definition suggests a singular noun but the answer is not.
'with the end cut off' is the wordplay.
'the end' says to take the final letters.
'cut off' becomes 'ah' (I can't explain this - if you can you should believe this answer much more).
The last letter of 'with' is 'h'.
'h'+'ah'='HAH'
Can you help me to learn more?
(Another definition for hah that I've seen is " Expression of surprise (one letter short of a laugh)".)