  We theoretically study low-temperature properties of the antiferromagnetic
Heisenberg model with half-integer spin $S$ on the Kagome lattice with large
trimerization. We have derived a low-energy effective model for general $S$ in
terms of spin and nematicity operators in triangular units, and studied their
low-temperature correlations for $S$=$3/2$ by classical Monte Carlo
simulations. The previous study for the $S$=$1/2$ case [M. Ferrero et al.,
Phys. Rev. B 68, 214431 (2003)] reported a spin liquid state at low
temperatures driven by a glassy behavior of isolated dimers and trimers of
nematicities. The results for $S$=$3/2$ show that nematicity dimers and trimers
are connected by weak links to form a defective planar network. At very low
temperatures, nematicities show glassy slow dynamics, and cluster spins
continue to fluctuate in a nonperiodically frozen background of nematicities.
The characteristic time of glassy dynamics scales with temperature following a
power law.
