  The four-flavor hard-wall holographic QCD is studied to evaluate the
couplings of $(D^{_{-(*-)}}, \bar{D}^{_0}, a_1^{_-})$, $(D^{_{-(*-)}},
\bar{D}^{_0}, b_1^{_-})$, $(D_{s}^{_{-(*-)}},\bar{D}^{_0}, K_{1A}^{_-})$,
$(D_s^{_{-(*-)}}, \bar{D}^{_0}, K_{1B}^{_{-(*-)}})$, $(D_s^{_{+(*+)}}, D^{_+},
K_{1A}^{_0})$, $(D_s^{_{+(*+)}}, D^{_+}, K_{1B}^{_0})$, $(D^{_{-(*-)}},
\bar{D}^{_{0(*0)}}, \rho^{_-})$, $(D_s^{_{-(*-)}}, \bar{D}^{_{0(*0)}},
K^{_{*-}})$, $(D^{_{0(*0)}}, \bar{D}^{_{0(*0)}}, \psi)$, $(D_1^{_-},
\bar{D}_1^{_0}, \pi^{_-})$, $(D_{s1}^{_-}, \bar{D}_1^{_0}, K^{_{-}})$,
$(D_1^{_0}, \bar{D}_1^{_0}, \eta_c)$, $(\psi, D^{_{0(*0)}}, D^{_+}, \pi^{_-})$,
$(\psi, D^{_{0(*0)}}, \bar{D}^{_0}, \pi^{_0})$, $(\psi, D_{s}^{_{+(*+)}},
D^{_-}, K^{_0})$, $(\psi, D^{_{0(*0)}}, D^{_+}, a_1^{_-})$, $(\psi,
D^{_{0(*0)}}, D^{_+}, b_1^{_-})$, $(\psi, D_s^{_{+(*+)}}, D^{_-}, K_{1B}^{_0})$
and $(\psi, D_s^{_{+(*+)}}, D^{_-}, K_{1B}^{_0})$ vertices. Moreover, the
values of the masses of $D^{_{0(*0)}}$, $D_s^{_{-(*-)}}$, $\omega$, $\psi$,
$D_1^{_0}$, $D_1^{_{-}}$, $K^0$, $\eta_{c}$, $D_{s1}^{_-}$ and $\chi_{_{c1}}$
as well as the decay constant of $\pi^-$, $D^{_{-(*-)}}$, $K^-$, $\rho^-$,
$D_1^{_-}$ , $a_1^-$ and $D_s^{_{-(*-)}}$ are estimated in this study. A
comparison is also made between our results and the experimental values of the
masses and decay constants. Our results for strong couplings are also compared
with the 3PSR and LCSR predictions.
