Select the most appropriate meaning of the given idiom.
Get itchy feet

The correct answer is To start to want to travel or do something different.

Explanation:
The idiom "get itchy feet" is a common English expression used to describe a strong urge or desire to travel, explore new places, or change one's current situation by doing something different. The metaphor refers to the feeling of restlessness or the sensation that one's feet "want to move" or start walking/traveling.
Let us evaluate the options provided:

• "Judge something primarily on appearance" refers to the idiom "judge a book by its cover".
• "Learn something by memorising it without a thought to what is being learnt" refers to the phrase "learn by rote" or "parrot fashion".
• "To start to want to travel or do something different" is the exact meaning of "get itchy feet".
• "Join a popular trend or activity" refers to the idiom "jump on the bandwagon".