Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
combat [n ˈkɔmbæt] [vt kəmˈbæt] n (fighting) бой#; (battle) би́тва
vt боро́ться*(impf) про́тив +gen
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.