Origin: Latin suffix -al
Motivational has 2 different meanings across 1 category:
of or relating to motivation
"The motivational speech inspired the team to work harder than ever before."
Tending or intended to motivate.
"The motivational speech gave the team the energy they needed to win."
In plain English: Motivational means something that gives you energy and pushes you to keep going toward your goals.
"The motivational speech gave everyone the energy to finish their projects on time."
The word motivational comes from combining the root motivation with the suffix -al to form an adjective describing something that provides motivation. It entered English as a straightforward grammatical adaptation of the existing noun rather than through borrowing or meaning shift.