Of poor quality; inferior or unsatisfactory; resembling or full of excrement.
From crap (excrement or rubbish) with the adjectival suffix -y. While 'crap' has Anglo-Saxon roots, 'crapy' is a modern colloquial formation, very productive in informal English.
This is a perfect example of how English speakers instantly understand new adjectives they've never heard before—add '-y' to almost any noun and you get an adjective. 'That movie was crapy' is instantly clear even though it's slangy.
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