From the Online Etymology Dictionary:
impostor 1580s, from M.Fr. imposteur (16c.), from L.L. impostor, agent noun from impostus, collateral form of impositus, pp. of imponere “place upon, impose upon, deceive,” from assimilated form of in- “into, in, on, upon” (see in- (2)) + ponere “to put in place” (see position).
home (n.) O.E. ham “dwelling, house, estate, village,” from P.Gmc. *haimaz (cf. O.Fris. hem “home, village,” O.N. heimr “residence, world,” heima “home,” Dan. hjem, M.Du. heem, Ger. heim “home,” Goth. haims “village”), from PIE base *tkei- “to lie, settle down” (cf. Skt. kseti “abides, dwells,” Armenian shen “inhabited,” Gk. kome, Lith. kaimas “village;” O.C.S. semija “domestic servants”).
homeless (adj.) 1610s, from home + -less. O.E. had hamleas, but the modern word probably is a new formation. As a noun meaning “homeless persons,” by 1857.
homelessness 1814, from homeless + -ness.