Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
mushy [ˈmʌʃɪ] adj рази́вшийся, как ка́ша (inf)(pej)(story, fiction) слаща́вый/слаща́в
mushy peas горо́шек
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.