seeming to have a reason; appearing to be for some cause
Archaic adjectival noun describing someone or something that looks like there is a particular reason or circumstance behind it. Not used in modern Japanese.
彼の故ありげな様子に、皆が気づいた。
Everyone noticed his manner that seemed to have some reason behind it.
Variant spelling with 気; also archaic.
Compound of 故 (yue, 'reason') + あり (ari, 'to exist') + げ (ge, suffix meaning 'seeming'). The exact historical derivation is uncertain, but the word follows a common pattern for archaic adjectival nouns.