Warning not working on wine bottle? (3,4)
I believe the answer is:
red flag
'warning not working on wine bottle?' is the definition.
'red flag' can be an answer for 'warning' (I've seen this before). I'm not certain of the 'not working on wine bottle?' bit.
'on wine bottle?' is the wordplay.
'on' says to put letters next to each other.
'wine' becomes 'red' (red is a type of wine).
'bottle?' becomes 'flag' (I can't explain this - if you can you should give a lot more credence to this answer).
'red'+'flag' is 'RED FLAG'.
Can you help me to learn more?
(Other definitions for red flag that I've seen before include "Warning to stop" , "Revolutionary symbol and song to the tune of Tannenbaum" , "left-wing message?" , "Socialist banner?" , "Instruction to halt" .)