YES

(VAR x)
(RULES
  g(x) -> f(f(x))
)

(COMMENT
Termination is shown by EKBO with interpretations on natural numbers

  f_A(x1) = 1
  g_A(x1) = 2

weights

  w0 = 1
  w(f) = 1
  w(g) = 3

and precedence:

g > f
)