FTthThth: Each ordinal numeral is derived, through the same pattern, from the root  of the corresponding cardinal numeral, with the exception of the numeral ‘first,’ whose form is suppletive. This is also known as the “first, twoth, threeth” type.

(S. O.)

In Synja Khanty, ordinal numerals are formed with the -met derivational suffix. The numeral meaning ‘first’ has a suppletive form. The cardinal numeral kat ‘two’ originates from the same stem etymologically as its corresponding ordinal numeral kimet ‘second’ (Honti 1984: 77), thus the ordinal numeral cannot be regarded as an irregular form.