This is the 13609th most frequent Russian word.
недостаточной
"Insufficient"
"Недостаточной" describes the motivation as being inadequate or not enough to reach the specified goal.
Её мотивация оказалась недостаточной для достижения цели.
Her motivation turned out to be insufficient for achieving the goal.
"Недостаточной" refers to the reason being considered not significant enough to justify the action.
Качество еды в ресторане показалось мне недостаточной причиной для возврата.
The food quality in the restaurant seemed to me an insufficient reason for refund.
"Недостаточной" pertains to the device's memory being inadequate or limited for storing data.