"Only / No more than" (scarcity)
Note: しか replaces が and を, but attaches after other particles.
"Have no choice but" (lack of alternatives)
Note: In the "have no choice but" usage, ない is part of しかない itself (no separate negative verb).
The pattern しかない expresses limitation or lack of alternatives. It has two main uses depending on what comes before it.
When attached to a noun, number, or counter, しか pairs with a negative verb to mean "only," "no more than," or "as few/little as." This usage emphasizes that the amount is insufficient or surprisingly small compared to what is expected.
しか replaces the particles が and を, but attaches after other particles like に, で, and へ:
しか vs. だけ: Both can mean "only," but しか~ない carries a stronger nuance of insufficiency or disappointment, while だけ is more neutral. Compare: みっつ三つだけある (There are just three – neutral) vs. みっつ三つしかない (There are only three – implying it's not enough).
When attached to a verb in dictionary form, しかない means "have no choice but to" or "can only do." This expresses that there is no other option available.
This usage conveys a sense of resignation – the speaker acknowledges that all other options have been exhausted.