Hi MG

My guess is that it is the suffix -ish (as in selfish) used in a more colloquial way. Here's what the Australian Macquarie dictionary has to say:

ish
1. a suffix used to form adjectives from nouns, with the sense of: a. `belonging to' (a people, country, etc.), as in British, Danish, English, Spanish. b. `after the manner of', `having the characteristics of', `like', as in babyish, girlish, mulish (such words being now often depreciatory). c. `addicted to', `inclined or tending to', as in bookish, freakish. 2. a suffix used to form adjectives from other adjectives, with the sense of `somewhat', `rather', as in oldish, reddish, sweetish. [Middle English, from Old English -isc]

How's that? Answer your question? I love the -ish additive - use it all the time.