This noun denotes defilement, pollution, or contamination, particularly in ritual or moral contexts. Nehemiah uses it to describe how the priesthood has been defiled or corrupted. The construct form 'defilements of' links it directly to the priesthood and covenant, suggesting violations of sacred trust. Such defilement could involve unlawful marriages, improper ritual conduct, or compromise with foreign practices—all concerns prominent in post-exilic reforms. The term emphasizes the serious breach of holiness standards.