Clear[Foop]
Foop[Power[#, Rational[1, 2]]&] = 2
Foop[Tan[#]&] = 3
Foop[Abs[#]&] = 4
Foop[1/#&] = 5

Clear[Test]
Test =
  {Foop[With[{c = Sqrt[#]}, Function[c]]],
   Foop[With[{c = Tan[#]}, Function[c]]],
   Foop[With[{c = Abs[#]}, Function[c]]],
   Foop[With[{c = 1/#}, Function[c]]]}
