not related to or following the rules of geometry; lacking geometric properties or arrangement.
From Greek 'a-' (not) combined with 'geometrical.' The prefix 'a-' meaning 'without' or 'not' is used to negate the mathematical/scientific property of being geometric.
While 'non-geometric' or 'ungeometric' are standard today, 'ageometrical' is a delightfully archaic way to describe something—it sounds like it belongs in a Victorian mathematician's complaint about abstract art.
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