  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.
