Here's what rhymes with manifestly.

Consider these alternatives

plainly / mainly grossly / closely illogical / logical antithetical / theoretical shamefully / painfully unsuited / routed pathetically / theoretically immoral / moral unreasonably / reasonably catastrophically / philosophically untrue / you unfair / their unjustified / side unjustifiable / viable misguided / decided astoundingly / resoundingly counterproductive / productive wrongheaded / longheaded shortsighted / decided