on ice —(coll.)
1. in reserve; in readiness:
- She’s never been able to find a man good enough for her, and so she’s keeping herself on ice.
2. said of smth. which is a sure thing, a certainty:
- I haven’t signed on the dotted line yet, but it’s on ice.
3. in detention:
- Scotland Yard could not keep him on ice that long. He would have to be brought to a court to be charged.
on thin ice—in a delicate or potentially difficult situation:
- Though he had a graduate business degree, he felt on thin ice when it came to financial investments.
See also: in cold storage / in the deep freeze.