Assess for a purpose

• Pay-to-graze fee
• Fee for grazing cattle
• Disparager of seniors
• Feed livestock for a fee
• Certain discriminator
• Feed for a fee, as cattle
• Discriminator against the elderly
• Like some hiring practices

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Agist \A*gist"\, v. t. [OF. agister; [`a] (L. ad) + gister to assign a lodging, fr. giste lodging, abode, F. g[^i]te, LL. gistum, gista, fr. L. jacitum, p. p. of jac?re to lie: cf. LL. agistare, adgistare. See Gist .] (Law) To take to graze or pasture, ...

Wiktionary Word definitions in Wiktionary
vb. To take to graze or pasture, at a certain sum; used originally of the feeding of cattle in the king's forests, and collecting the money for the same.