Ostensible

/ɒˈstɛnsəbəl/ adjective hard

Appearing or claimed to be true, though the real reason may be different.

The ostensible reason for the meeting was budget planning, but everyone knew layoffs would be discussed.

Memory Trick

It is related to ostentatious, meaning showy, so the ostensible reason is the one shown on the surface, not necessarily the one underneath.