Pecuniary, a.
Etymology: [L. pecuniarius, fr. pecunia money, orig., property in cattle, fr. pecus cattle: cf. F. pécuniaire. See Fee, and cf. Peculiar.]
1. Relating to money; monetary; as, a pecuniary penalty; a pecuniary reward. Burke.
Shades of meaning
Fernald has no entry of its own for pecuniary; he lists it under financial.
Where he writes about it:
Pecuniary refers to that in which money is involved, but less directly; we speak of one's pecuniary affairs or interests, with no special reference to the handling of cash. — from financial
Financial applies especially to governmental revenues or expenditures, or to private transactions of considerable moment; we speak of a pecuniary reward, a financial enterprise; we give a needy person pecuniary (not financial) assistance. — from financial