In the manner of a bride; in a way related to or characteristic of bridal customs or ceremonies.
From bridale or bridal plus adverbial suffix -ly. This forms an adverb describing actions or states related to bridal circumstances.
Adding -ly to adjectives is one of English's most productive word-making tools, but bridally shows how we rarely need this form since 'in a bridal manner' is clearer—sometimes not every possible word survives use.
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