When using this grammar with an adjective or verb, you can only use those that express emotions or feelings of the heart. For example, うれしげ、悲しげ、楽しげ、不安げ、自信ありげ.
FORMATION: いＡ(take off い)+げ なＡ+げ Ｖ[〜ありげ]
〜げだ 〜げに+Ｖ 〜げな+Ｎ
〜げcan be used for i- and na-adjectives
I'm not sure, but I'd guess 大人げない follows a similar pattern to 何げない、さりげない、すげない etc., rather than following this grammar pattern. Adjectives combined with げ inflect as ーな adjectives. 大人げない doesn't seem to work that way.
Generally used with i adjectives for feelings / emotions.
Is there a げ used for N adjectives?
bamboo4, I thought 大人げない is a good example but is this irregular? This is different from others. 大人げ is always followed by ない. 大人げ が ない or 大人げない.
Formed from Adjective base + ge (e.g. i-adjectives lose final i) Ab = Adjective Base