Synonyms for Bedamn:

n.

bedamn (noun)
beshrew, maledict, imprecate, anathemize, curse.

v.

swear (verb)
curse, imprecate.

Other synonyms:

n.
anathemize, beshrew, curse, imprecate, maledict.
Other relevant words:
curse, imprecate, maledict.