big if

big if (plural big ifs)

1. An unlikely but necessary condition.
   • 1868 Montgomery Schuyler, The Pioneer Church: Or, The Story of a New Parish in the West (Boston: Riverside Press, 1868), p. 2:

     "If I were only old enough," said Kate, "and knew enough to teach a day-school, I would begin at once and save half of my money [...]."

     "Oh!" Edward replied, "there's a big if in the way."

   • 2004, Dale Brown, Dreamland: Strike Zone, HarperCollins, →ISBN, page 217,

     "If they believe us," said the admiral, "and that's a big if, then we're in a race with them to find this thing. Because if they grab it—"

   Coordinate term: small if

• tall order

• “big if”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.
• “big if”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.
• “and it s a big if” in Longman Dictionary of Contemporary English, Longman.