An oven faulty at the bottom end will do you no good! (5)
I believe the answer is:
venom
'do you no good' is the definition.
I can't tell whether this definition defines the answer.
'an oven faulty at the bottom end' is the wordplay.
'faulty' indicates an anagram.
'at' means one lot of letters go next to another.
'end' indicates one should take the final letters.
The final letter of 'bottom' is 'm'.
'oven' anagrammed gives 'veno'.
'veno'+'m'='VENOM'
'will' acts as a link.
Can you help me to learn more?
(Other definitions for venom that I've seen before include "Poisonous liquid of snakes" , "ill will" , "bitterness" , "Virulent feeling" , "Toxic substance" .)