Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
acquaintance [əˈkweɪntəns] n (person) знако́мый[-ая] m(f) adj ; (with person, subject) знако́мство
to make sb's acquaintance познако́миться*(perf) с кем-н
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.