obligatorily

from WordNet (r) 3.0 (2006)

obligatorily
    adv 1: in an obligatory manner; "this rule applies obligatorily"
           [ant: {optionally}]
    2: in a manner that cannot be evaded; "the ministry considers
       that contributions to such a fund should be met from
       voluntary donations rather than from rates compulsorily
       levied." [syn: {compulsorily}, {obligatorily}, {mandatorily}]

from The Collaborative International Dictionary of English v.0.48

Obligatorily \Ob"li*ga*to*ri*ly\, adv.
   In an obligatory manner; by reason of obligation. --Foxe.
   [1913 Webster]