Select the most appropriate meaning of the underlined idiom.

When the war breaks out, all the war mongering social media activists become yellow bellies.

Cowards

The most appropriate meaning of the underlined idiom "yellow bellies" in the given sentence is cowards.

The idiom "yellow bellies" is used to describe someone who is afraid to fight or who is not brave. It is often used to describe someone who talks tough but is not willing to back up their words with action.

In the given sentence, the speaker is saying that all the war mongering social media activists become cowards when the war breaks out. This means that they are all talk and no action.

The other options are incorrect:

• Zealots: Zealots are people who are very passionate about their beliefs and who are willing to fight for them.
• Sceptics: Sceptics are people who are doubtful or questioning.
• Upset stomachs: Upset stomachs are caused by nausea or indigestion.