As

As is the connective to compare the similarities of two ideas. Like "like", this is called the simile. But as is more often used in idioms specific to English:

• "Green as grass"
• "Right as rain"

Usually, one idea is more abstract and the other is more concrete - and the connective is intended to be more general than just one situation. When this is so, using "as" may imply that the conceptual metaphor is in effect in other statements:

• "Love as war"
• "Time as the path"

In other words, you can say more generally what an idiom or metaphor says: for example, "battle of the sexes" is both the metaphor and an idiom that suggests "love as war".

Because of this power, you can restate an idiom or metaphor in the way that makes it clear what it means, and what it might assume.