To fathom out something is to finally understand something deep or puzzling. Fathom out the instructions, cannot fathom out why.
It is used most in the negative, since people report what they could not fathom out. A fathom is six feet of depth, and the word meant measuring how deep water was before it meant understanding.
1phrasefathom outTo finally understand something deep or puzzling.
“Nobody could fathom out why the machine stopped on Tuesdays.”
fathom out is a phrase.
Practised in Thinking & Memory