purmo -pum-pu'o- gismu

x1 is a powder of material x2.

Flour (= grupu'o, xripu'o). See also pulce, zalvi.

In notes:

pulce
x1 is dust/precipitate [suspensible solid] from x2 in medium/on surface x3.
zalvi
x1 [individual or mass of hard surfaces] grinds/pulverizes/crushes x2 into powder x3.
pumlumci
l1 (agent) dusts l2 with l4
pumvau
v1 contains powder of material p2.