ostensible
/ɔˈstensəbl; ɑs`tɛnsəbl/ adj[attrib 作定语]
stated (as a reason, etc) though perhaps not true; apparent 声称（为理由等）的; 表面的
The ostensible reason for his absence was illness, but everyone knew he'd gone to a football match. 他称病缺席, 但谁都知道他去看足球赛了.