1.
If a person or situation loosens up , they become more relaxed and less tense.
Young people often loosen up on the dance floor...
I think people have loosened up their standards.
PHRASAL VERB : V P , V P n
2.
If you loosen up your body, or if it loosens up , you do simple exercises to get your muscles ready for a difficult physical activity, such as running or playing football.
Squeeze the foot with both hands, again to loosen up tight muscles...
Close your eyes. Relax. Let your body loosen up.
PHRASAL VERB : V P n (not pron) , V P , also V n P