be at sea

be at sea

1. To literally sail on the sea in a boat or ship. A: "Is your mother at sea yet?" B: "Yes, her cruise lasts several weeks."
2. To be puzzled, perplexed, or completely confused (about a subject or some task at hand). I tried to do well in this class, but I've been at sea since we started.
See also: sea
Farlex Dictionary of Idioms.

at sea, to be/all

To be bewildered, to have lost one’s way. Presumably it reflects the idea of literally having lost one’s bearings while at sea. It was so used by Dickens and other nineteenth-century writers.
See also: all
The Dictionary of Clichés by Christine Ammer
See also:
  • at sea
  • sea
  • all at sea
  • all, completely, etc. at sea
  • at sea, to be/all
  • completely
  • mutiny
  • mutiny against
  • mutiny against (someone or something)
  • put (out) to sea