The Collaborative International Dictionary of English v.0.48:

Nonsuit \Non"suit`\, v. t. [imp. & p. p. Nonsuited; p. pr. &
   vb. n. Nonsuiting.] (Law)
   To determine, adjudge, or record (a plaintiff) as having
   dropped his suit, upon his withdrawal or failure to follow it
   up. "When two are joined in a writ, and one is nonsuited."
   --Z. Swift.
   [1913 Webster]