Vehicle attachment will make one exhausted, I say (4)
I believe the answer is:
tyre
'i say' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'vehicle attachment will make one exhausted' is the wordplay.
'vehicle attachment' becomes 'ty' (I can't explain this - if you can you should believe this answer much more).
'will' says to put letters next to each other (I've seen this in other clues).
'make' becomes 'realise' (realise can mean to create or carry out).
'one exhausted' means to remove the middle letters (the word is emptied out or exhausted).
'realise' with its middle removed is 're'.
'ty'+'re'='TYRE'
Can you help me to learn more?
(Other definitions for tyre that I've seen before include "Wheel cover, may be tubeless" , "Something with a tread" , "Rubber surround on a wheel" , "Travelling band" , "Phoenician city" .)