1stab 
/ˈstæb/ noun
plural stabs /ˈstæb/ noun [count] 1 : a wound made by a pointed weapon (such as a knife)
▪ He died from a stab to the heart. [=died from being stabbed in the heart] ▪ a stab wound/victim 2 : a sudden, strong feeling of physical or emotional pain — + of ▪ a stab of pain/regret/doubt/fear 3 informal : an attempt to do something successfully — often + at ▪ She took/made a stab at solving the problem. [=she made an attempt to solve the problem] ▪ Let me give it a stab. = Let me have a stab at it. [=let me try to do it]
▪ He died from a stab to the heart. [=died from being stabbed in the heart] ▪ a stab wound/victim
a stab in the back
: an action or way of behaving that hurts someone who trusts you : an act of betrayal
▪ I can't believe that someone I had helped and supported would steal from me. It's a real stab in the back.
▪ I can't believe that someone I had helped and supported would steal from me. It's a real stab in the back.
a stab in the dark 1 : a guess that is based on very little or no information or evidence
▪ They don't really know how much the work will cost. They're just taking a stab [=shot] in the dark. 2 : an attempt that is not likely to succeed
▪ It's a stab [=shot] in the dark, but we should try anyway.
▪ They don't really know how much the work will cost. They're just taking a stab [=shot] in the dark.
▪ It's a stab [=shot] in the dark, but we should try anyway.
