KVertexConnectedGraphQ
KVertexConnectedGraphQ[g, k] yields True if the graph g is k-vertex-connected and False otherwise.
Examples
Check if a graph is 2-vertex-connected:
KVertexConnectedGraphQ[CompleteGraph[5], 2]
(* True *)KVertexConnectedGraphQ[PathGraph[{1, 2, 3}], 2]
(* False *)Please visit the official Wolfram Language Reference for more details.