Etymology From Middle English -ish, -isch, from Old English -isċ (“-ish”, suffix), from Proto-West Germanic *-isk, from Proto-Germanic *-iskaz (“-ish”), from Proto-Indo-European *-iskos. Cognate with Dutch -s; German -isch (whence Dutch -isch); Norwegian, Danish, and Swedish -isk or -sk; Lithuanian -iškas; Russian -ский (-skij); and the Ancient Greek diminutive suffix -ίσκος (-ískos). Doublet of -esque and -ski.
1
Morpheme, Of adjectives from common nouns Typical of, similar to, being like.
Her face had a girlish charm.
[…] ; for she had recently developed a magpie[-]ish tendency to appropriate and conceal trifling matters; […]1859, Harriet Parr (as Holme Lee), Against Wind and Tide, volume 1, p. 273
2
Morpheme, Of adjectives from adjectives, With a diminutive force Somewhat, rather.
Her face had a bluish tinge.
By one o'clock the place was choc-a-bloc. […] The restaurant was packed, and the promenade between the two main courts and the subsidiary courts was thronged with healthy-looking youngish people, drawn to the Mecca of tennis from all parts of the country.1935, George Goodchild, chapter 5, in Death on the Centre Court:
3
Especially, Morpheme, Of adjectives from numbers, Of times and ages About, approximately.
We arrived at tennish. We arrived tennish.
I couldn't tell his precise age, but he looked fiftyish.
4
Morpheme Of, belonging, or relating to (a nationality, place, language or similar association with something).
Of adjectives from roots of proper nouns denoting names of nations or regions
Etymology From Middle English -ishen, -ischen, -issen, from Old French -iss-, -is- (a termination of the stem of some forms [present participle, etc.] of certain verbs), from Latin -ēscere, -īscere (an inchoative suffix), the formative -esc-, -isc- (-sc-, Greek -σκ- (-sk-)) being ultimately cognate with English -ish (Etymology 1). See -esce, -escent, etc.
1
Idiomatic, Morpheme An ending found on some verbs; see usage notes.