The Collaborative International Dictionary of English v.0.48:
Filter \Fil"ter\, v. t. [imp. & p. p. Filtered; p. pr. & vb.
n. Filtering] [Cf. F. filter. See Filter, n., and cf.
To purify or defecate, as water or other liquid, by causing
it to pass through a filter.
Filtering paper, or Filter paper, a porous unsized paper,
Moby Thesaurus II by Grady Ward, 1.0:
38 Moby Thesaurus words for "filtering":
bolting, clarification, colature, destructive distillation,
distillation, edulcoration, effusion, elution, elutriation,
essentialization, excretion, exfiltration, extraction,
extravasation, exudation, filtration, leaching, lixiviation, ooze,
oozing, percolating, percolation, purification, refinement,
riddling, screening, seep, seepage, separation, sieving, sifting,
spiritualization, straining, sublimation, transudation, weep,