way off base

off base

Incorrect; mistaken or misinformed; not aligned with reality. An allusion to baseball, in which baserunners are only "safe" if their foot is touching a "base." Hyphenated if used before a noun. Primarily heard in US. Your arguments would be compelling if your entire premise wasn't completely off base. You need to stop making these off-base assumptions about how the process works.
See also: base, off
Farlex Dictionary of Idioms.

way off (base)

mod. on the wrong track; completely wrong. (see also off base.) Sorry. You are way off. You should just give up.
See also: base, off, way
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • off base
  • way off
  • get (one's) wires crossed
  • get one's wires crossed
  • get your wires crossed
  • have (one's) wires crossed
  • have wires crossed
  • strike out at (something or some place)
  • hit (something) out of the (ball)park
  • game is not worth the candle, the