na-adjective
comprehensive; exhaustive; encyclopedic
Describes something that covers all relevant items or aspects without omission. Often used for lists, surveys, databases, or knowledge.
このデータベースは網羅的な情報を提供している。
This database provides comprehensive information.
彼の知識は実に網羅的だ。
His knowledge is truly encyclopedic.
徹底的 means thorough or exhaustive in a more action-oriented sense, focusing on doing something completely rather than covering all items.
From 網羅 (もうら, 'covering all, including all') + 的 (てき, '-like, -ic'). 網羅 is composed of 網 (もう, 'net') and 羅 (ら, 'gauze, net'), metaphorically suggesting catching everything in a net.