Hi, the -ish suffix is to make the meaning of the word “more or less” or not exactly. like yellow-ish means it’s not exactly yellow, it’s a little off color, maybe a little orange in it or another color. Not pure yellow. 9-ish means not exactly 9 o’clock, a little before or after but not on the dot. It’s the same for any word so it implies the meaning is not exact. I hope this helps.

In this context, it means approximately. New Oxford American Dictionary -ish suffix 2 (forming adjectives from adjectives) somewhat: yellowish. • informal (forming adjectives) denoting an approximate age or time of day: sixish. ======= Oxford Learner's Dictionaries https://www.oxfordlearnersdictionaries.com/definition/english/ish_2 -ish suffix in adjectives 3 - ​fairly; approximately reddish thirtyish

Hello David and Matthew, Thank you for your help. :)

9-ish, smallish, and yellowish are very conventional. "great-ish" isn't and doesn't sound that great because "great" isn't that precise to begin with. "boyfriendish" is also non-standard but sounds rather humorous and clever.

-ish has at least two different functions when used with English words. In all the examples you gave it is being used to express imprecision or approximation. This is by far the more common usage in today's English. However, in a more literary sense the -ish suffix is one way of turning a noun into an adjective. If a child is described as "bookish" it means she is inclined to spend a lot of time reading or studying. In the particular case of "boyfriendish", this is supposed to be humorous I think. In many more conservative and traditional views of romantic relationships, being a boyfriend/girlfriend was considered to be almost a formal arrangement which is to say it was exclusive. Along with cultural shifts in expectations between romantic partners, there is new language necessary to communicate vaguely defined romantic relationships.