  The microscopic details of the suppression of antiferromagnetic order in the
Kondo-lattice series Ce$_{1-x}$La$_{x}$Cu$_{2}$Ge$_{2}$ due to nonmagnetic
dilution by La are revealed through neutron diffraction results for $x=0.20$,
$0.40$, $0.75$, and $0.85$. Magnetic Bragg peaks are found for $0.20\le
x\le0.75$, and both the N\'{e}el temperature, $T_{\textrm{N}}$, and the ordered
magnetic moment per Ce, $\mu$, linearly decrease with increasing $x$. The
reduction in $\mu$ points to strong hybridization of the increasingly diluted
Ce $4f$ electrons, and we find a remarkable quadratic dependence of $\mu$ on
the Kondo-coherence temperature. We discuss our results in terms of
local-moment- versus itinerant-type magnetism and mean-field theory, and show
that Ce$_{1-x}$La$_{x}$Cu$_{2}$Ge$_{2}$ provides an exceptional opportunity to
quantitatively study competing magnetic interactions in a Kondo lattice.
