Russian -ой

The adjectives and adjectival words are registered in the dictionaries in the masculine and they end in -ый or -ой or -ий.

You can make other gender forms by changing the endings as follow:

• When modifided noun is feminine (end with -а or -я) the adjective will end in -ая or -яя
• When modifided noun is neuter (end with -о or -е) the adjective will end in -ое or -ее
• When modifided noun is plural (end with -и or -ы) the adjective will end in -ые or -ие