Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
rut [rʌt] n (groove) колея́, борозда́# (ZOOL) (season) полова́я охо́та
to get into a rut (fig) заходи́ть*(зайти́*perf) в тупи́к, застрева́ть (застря́ть*perf)
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.