并非 (bìng fēi) is a verb meaning 'it is not the case that' — it negates a whole statement or noun phrase, often in formal or written contexts. Unlike the adverbs 绝 (jué) and 万万 (wàn wàn), which intensify a following negation (绝/万万 + 不/没), 并非 itself carries the negation and is used to deny a fact or assumption. 万万 often adds a sense of warning or strong advice, while 绝 is more about absolute denial.