make a stab at
Try to do something, as in I don't know the answer but I'll make a stab at it. This expression derives from stab in the sense of “a vigorous thrust.” [Late 1800s] Also see make a pass at, def. 2.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.