-еский

Etymology
, from. of.

Suffix

 * : -ian, -ic, -ish

Usage notes

 * Usually occurs after stems historically ending in velar consonants (synchronically in /к/, /г/, /х/, /ц/, /з/). Triggers the first Slavic palatalisation.
 * The adverb is.
 * The longer suffixes and  were generalized through rebracketing of nouns with roots ending in к and ик respectively.