  If the Higgs boson is a pseudo Nambu-Goldstone boson (PNGB), the $hZ\gamma$
contact interaction induced by the $\mathcal{O}(p^4)$ invariants of the
non-linear sigma model is free from its nonlinearity effects. The process
$h\rightarrow Z\gamma$ can be used to eliminate the universal effects of heavy
particles, which can fake the nonlinearity effects of the PNGB Higgs boson in
the process $h\rightarrow V^*V$ ($V=W^\pm$,\ $Z$). We demonstrate that the
ratio of the signal strength of $h\rightarrow Z\gamma$ and $h\rightarrow V^*V$
is good to distinguish the signature of the PNGB Higgs boson from Higgs
coupling deviations.
