FreeQ

FreeQ[expr, form] yields True if no subexpression in expr matches form, and False otherwise.

Examples

Check if expression is free of a symbol:

FreeQ[x^2 + y, z]
(* True *)

FreeQ[x^2 + y, x]
(* False *)

With patterns:

FreeQ[{a, b, c}, _Integer]
(* True *)

Please visit the official Wolfram Language Reference for more details.