Unusual ferrimagnetism in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow><mml:mi>Ca</mml:mi><mml:msub><mml:mi>Fe</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mn>4</mml:mn></mml:msub></mml:math>

Incomplete cancellation of collinear antiparallel spins gives rise to ferrimagnetism. Even if the oppositely polarized are owing equal number a single magnetic element having same valence state, in principle, ferrimagnetic state can still arise from crystallographic inequivalence host ions. However, experimental identification such as ``ferrimagnetic'' is not straightforward because often tiny magnitude expected for $M$ and requirement sophisticated technique differentiate similar sites. We report synchrotron-based resonant x-ray investigation at Fe ${L}_{2,3}$ edges on an epitaxial film $\mathrm{Ca}{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$, which exhibits two phases with energies. find that while one phase $\mathrm{Ca}{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$ antiferromagnetic, other arrangement between distinct sites very local coordination environments. Our results further indicate origins overall minute $M$; intrinsic, ${\mathrm{Fe}}^{3+}$ sites, extrinsic, arising defective ${\mathrm{Fe}}^{2+}$ likely forming weakly coupled clusters. These uncorrelated have different coercive fields. Hence, this work provides direct demonstration ferrimagnetism solely due origin weak $\mathrm{Ca}{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$.