WordNet (r) 3.0 (2006):

tax return
    n 1: document giving the tax collector information about the
         taxpayer's tax liability; "his gross income was enough that
         he had to file a tax return" [syn: tax return, income
         tax return, return]

Moby Thesaurus II by Grady Ward, 1.0:

31 Moby Thesaurus words for "tax return":
   assessment, cess, conscience money, contribution, direct tax, duty,
   graduated taxation, imposition, impost, indirect tax, joint return,
   levy, progressive tax, separate returns, single tax, supertax,
   surtax, tax, tax base, tax dodging, tax evasion, tax exemption,
   tax structure, tax withholding, tax-exempt status, taxable income,
   taxation, tithe, toll, tribute, withholding tax