Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
closely [ˈkləuslɪ] adv (watch, examine) при́стально; (connected, related) те́сно
he closely resembles his father он о́чень похо́ж на отца́
we are closely related мы бли́зкие ро́дственники
a closely guarded secret тща́тельно оберега́емый секре́т
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.
Русский: