[医] 抗, 对, 靠, 在前, 在上, 向

Ob- \Ob-\ [L. ob, prep. Cf. {Epi-}.]
A prefix signifying to, toward, before, against, reversely,
etc.; also, as a simple intensive; as in oblige, to bind to;
obstacle, something standing before; object, lit., to throw
against; obovate, reversely, or oppositely, ovate. Ob- is
commonly assimilated before c, f, g, and p, to oc-, of-, og-,
and op-.