inlandish (adj.)

"of or pertaining to interior parts of a country," 1550s, from in + land (n.). The noun meaning "interior parts of a country (remote from the sea or borders)" is attested from 1570s. Meaning "confined to a country" (as opposed to foreign) is from 1540s. In Middle English and Old English the same compound meant "land immediately around the mansion of an estate, land in the lord's own occupation (as opposed to land occupied by tenants)." Related: Inlander.

adjectival word-forming element, Old English -isc "of the nativity or country of," in later use "of the nature or character of," from Proto-Germanic suffix *-iska- (cognates: Old Saxon -isk, Old Frisian -sk, Old Norse -iskr, Swedish and Danish -sk, Dutch -sch, Old High German -isc, German -isch, Gothic -isks), cognate with Greek diminutive suffix -iskos. In its oldest forms with altered stem vowel (French, Welsh). The Germanic suffix was borrowed into Italian and Spanish (-esco) and French (-esque). Colloquially attached to hours to denote approximation, 1916.

The -ish in verbs (abolish, establish, finish, punish, etc.) is a mere terminal relic from the Old French present participle.