Imagine a wavefunction:
$$ \Psi = C_1 \psi_1 + C_2\psi_2 + C_3\psi_3 + C_4\psi_4 $$
where $C_1$, $C_2$, etc are all constants and $\psi_1$, $\psi_2$, etc are eigenfunctions.
If it is given that $\psi_2$ is orthogonal to $\Psi$ does it mean that the probability for the state $\psi_2$ is = 0. If it is so can some one explain this to me in simple terms?