The Collaborative International Dictionary of English v.0.48:
Inflexibly \In*flex"i*bly\, adv. In an inflexible manner. [1913 Webster]WordNet (r) 3.0 (2006):
inflexibly adv 1: in an inflexible manner; "`You will--because you must!,' Madam told her inflexibly" [ant: flexibly]