We study heavy photophobic axion-like particles (ALPs) in the limit of an effectively vanishing diphoton coupling, $g_{a\gamma \gamma }\simeq 0$, for which diphoton production and decay are suppressed and collider phenomenology is driven by electroweak interactions ($aWW$, $aZ\gamma$, $aZZ$). We perform detector-level searches at a future $\sqrt{s}=$ 100 TeV $pp$ collider (SppC/FCC-hh), with an integrated luminosity of $ℒ=$ 20 ab${}^{-1}$. We consider $a\to Z\gamma$ and $a\to W^{+}{W}^{-}$ decays. For $pp\to jja$ we include both $s$-channel electroweak exchange and vector boson fusion (VBF)-like topologies, while the tri-$W$ signature arises from associated production $pp\to W^{\pm }a$ (via $s$-channel exchange) followed by $a\to W^{+}{W}^{-}$. We analyze three final states–$Z\gamma jj$ with $Z\to {\ell }^{+}{\ell }^{-}$, tri-$W$ ($W^{\pm }{W}^{\pm }{W}^{\mp }$) with same-sign dimuons plus jets, and $W^{+}{W}^{-}jj$ with opposite-sign, different-flavor dilepton ($e^{\pm }{\mu }^{\mp }$) plus jets. Among the two $WW$ final states, the VBF-assisted $jja(\to W^{+}{W}^{-})$ channel overtakes the purely $s$-channel tri-$W$ mode for $m_a\gtrsim 1~\TeV$, reflecting 100~TeV signal/background kinematic shifts beyond naive energy/luminosity rescaling. A boosted-decision-tree (BDT) classifier built from kinematic observables provides the final signal–background separation, using detector-level simulations of signal and high-statistics SM backgrounds. At $\sqrt{s}=100$ TeV and $ℒ=$ 20 ab${}^{-1}$, we present discovery sensitivities to the ALP–$W$ coupling $g_{aWW}$ over $m_a\in [100,7000]$ GeV. In parallel, we report model-independent discovery thresholds on $\sigma \times Br$ for $pp\to jja$ with $a\to Z\gamma$ and $a\to W^{+}{W}^{-}$, as well as for associated production $pp\to W^{\pm }a$ with $a\to W^{+}{W}^{-}$. Taken together, the three channels deliver broad coverage and mutually reinforcing checks across decay modes and production regimes, strengthening robustness against channel-dependent systematics. The 100~TeV program extends the discovery reach well beyond 14~TeV projections within a general effective field theory (EFT) description that does not assume a specific ultraviolet completion.