to cross the Rubicon
- idiom
- Informal
- Deciding to quit my job without another lined up is like crossing the Rubicon; there's no turning back now.
- Caesar crossed the Rubicon
Examples
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In September 1988, Deng crossed the Rubicon by calling for price and wage reform.
Academic text (1998) -
I think what they're trying to say, Elizabeth, is that we've all just crossed the Rubicon.
-
We have truly crossed the Rubicon.
Blog text (28) -
We have crossed the Rubicon.
Blog text (15) -
"It's pretty clear that they crossed the Rubicon in 1950." The next campaign was an advance on the public school system.
Academic text (2004) -
So far, it's been all talk; none of them have crossed the Rubicon by calling for an actual major policy shift, even on immigration reform.
Blog text (18) -
When she decided to start her own business, she felt that she had crossed the Rubicon in her career.
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By voting in favor of the controversial policy, the council members crossed the Rubicon and committed themselves to significant changes.
Synonyms
To make a big decision you cannot change that may be risky
To decide to start something difficult and not change your mind
To decide to do something difficult and not stop
Antonyms
Surface Forms
Morphology
This phrase is a historical allusion (Julius Caesar crossing the Rubicon) whose idiomatic sense of an irreversible, decisive step depends on cultural knowledge rather than transparent composition. A B1 learner who only knows the literal meanings of 'cross' and the proper name 'Rubicon' would not reliably infer the metaphorical meaning, so the expression is not predictable from its parts.
Etymology
The verb cross the Rubicon comes from a famous moment in Roman history. In 49 BC, Julius Caesar led his army across the small river Rubicon, a border he was not allowed to pass, and that action started a civil war and could not be undone. So today cross the Rubicon means 'to take a decisive and irreversible step'.