# window.resizeable(width_bool,height_bool)
window.resizeable(FALSE,FALSE)
# window variable will typically be "root"
# See http://tkdocs.com/tutorial/windows.html#:~:text=window.resizable(FALSE%2CFALSE)
import tkinter as tk
root = tk.Tk()
root.resizable(width=False, height=False)
root.mainloop()