The Collaborative International Dictionary of English v.0.48:

Pelf \Pelf\ (p[e^]lf), n. [OE. pelfir booty, OF. pelfre, akin to
   pelfrer to plunder, and perh. to E. pillage. Cf. Pilfer.]
   Money; riches; lucre; gain; -- generally conveying the idea
   of something ill-gotten or worthless. It has no plural.
   "Mucky pelf." --Spenser. "Paltry pelf." --Burke.
   [1913 Webster]

         Can their pelf prosper, not got by valor or industry?
                                                  --Fuller.
   [1913 Webster]

WordNet (r) 3.0 (2006):

pelf
    n 1: informal terms for money [syn: boodle, bread,
         cabbage, clams, dinero, dough, gelt, kale,
         lettuce, lolly, lucre, loot, moolah, pelf,
         scratch, shekels, simoleons, sugar, wampum]

Moby Thesaurus II by Grady Ward, 1.0:

118 Moby Thesaurus words for "pelf":
   affluence, and pence, assets, bottomless purse, bulging purse,
   capital gains, cash, circulating medium, cleanup, clear profit,
   coinage, coined liberty, cold cash, currency, debris, dividends,
   dollars, earnings, easy circumstances, embarras de richesses,
   emergency money, filthy lucre, fortune, fractional currency, gain,
   gains, garbage, get, gettings, gleanings, gold, gross,
   gross profit, handsome fortune, hard cash, hard currency,
   high income, high tax bracket, hoard, income, independence,
   interest, junk, kelter, killing, legal tender, litter, lucre,
   luxuriousness, makings, mammon, managed currency, material wealth,
   mazuma, medium of exchange, mintage, money, money to burn,
   moneybags, moolah, neat profit, necessity money, needful, net,
   net profit, offal, ooftish, opulence, opulency, paper profits,
   percentage, perk, perks, perquisite, pickings, possessions,
   postage currency, postal currency, pounds, proceeds, profit,
   profits, property, prosperity, prosperousness, rake-off, receipts,
   return, returns, rhino, riches, richness, rubbish, scratch, scrip,
   shillings, silver, six-figure income, smash, soft currency, specie,
   sterling, store, stuff, stumpy, substance, take, take-in,
   the almighty dollar, the wherewith, the wherewithal, trash,
   treasure, upper bracket, waste, wealth, wealthiness, winnings