unspokenmotive
nounUK /ʌnˈspəʊkən ˈməʊtɪv/
US /ʌnˈspoʊkən ˈmoʊtɪv/
A reason for doing something that you keep secret and do not say out loud.
Her unspoken motive for helping was to make a new friend.
OTHER MEANINGS
2. A quiet wish that guides someone's actions without being told to others.
He gave the gift with an unspoken motive of saying sorry.
3. A hidden cause behind a choice that others cannot see.
The unspoken motive behind the rule was to keep everyone safe.
4. A private goal that a person does not admit, even to themselves.
Her unspoken motive for practicing daily was to win the contest.