Select the most appropriate meaning of the given Idiom:-

Gall and wormwood 

Bitterness and resentment

The most appropriate meaning of the idiom "gall and wormwood" is bitterness and resentment. The idiom comes from the idea of two bitter plants, gall and wormwood, which were used in ancient times to make a bitter drink. In a figurative sense, to say that someone is "gall and wormwood" means that they are filled with bitterness and resentment.

The other options are not as accurate descriptions of the meaning of the idiom. Two best friends are not typically associated with the idiom "gall and wormwood." Full devotion is not the same as bitterness and resentment. Someone inseparable is not typically associated with the idiom "gall and wormwood."