underruff

under- +‎ ruff

underruff (third-person singular simple present underruffs, present participle underruffing, simple past and past participle underruffed)

1. (bridge) To ruff with a trump lower than the trump already played by one's opponent
   • 1973, Fred L. Karpin, The Art of Card Reading at Bridge‎, →ISBN, page 149:

     And so, at trick five, when South ruffed a diamond with the board's queen of clubs, East, having a discard to make, found a gorgeous one— he underruffed with seven of trumps!

underruff (plural underruffs)

1. An act of underruffing

• ruff
• overruff