The term 'loosen up' can be expressed in a variety of ways, including 'RELAX' (5 letters), 'UNWIND' (6 letters), 'limer' (5 letters), 'THAW' (4 letters), 'LIMBER' (6 letters), 'WARM' (4 letters), 'UNTIE' (5 letters), 'HERESY' (6 letters), 'UNBEND' (6 letters), 'EXERCISE' (8 letters), and 'let one's hair down' (15 letters). All of these terms refer to the idea of loosening up, or relaxing, either physically or mentally. Physically, this could mean stretching, exercising, or limbering up; mentally, it could mean taking a break from work or stress, unwinding, or letting one's hair down.