動詞 relax:

1. become less tense, rest, or take one's ease
   同義詞：loosen up, unbend, unwind, decompress, slow down
2. make less tight
   同義詞：unbend
3. become loose or looser or less tight
   同義詞：loosen, loose
4. cause to feel relaxed
   同義詞：unstrain, unlax, loosen up, unwind, make relaxed
5. become less tense, less formal, or less restrained, and assume a friendlier manner
   同義詞：loosen up
6. make less severe or strict
   同義詞：loosen
7. become less severe or strict
   同義詞：loosen
8. make less active or fast
   同義詞：slack, slacken, slack up

1. The music will help to relax you.
   音樂會使你感到輕松。
2. His muscles relaxed.
   他的肌肉松弛了。

re.lax

v.（動詞）
re.laxed,re.lax.ing,re.lax.es
v.tr.（及物動詞）
To make lax or loose:
使放松或松弛：
例句：
relax one`s grip.
松開某人的掌握

To make less severe or strict:
放寬：使較不嚴(yán)厲或嚴(yán)格：
例句：
relax a curfew.
放松宵禁

To reduce in intensity; slacken:
松懈：減少緊張的程度；放松：
例句：
relax one`s efforts.
放松某人的努力

To relieve from tension or strain:
使輕松：由緊張或約束中釋放出來：
例句：
The warm bath relaxed me.
溫暖的沐浴使我放松

v.intr.（不及物動詞）
To take one`s ease; rest.
松散；休息
To become lax or loose.
松弛：變得松弛或松散
To become less severe or strict.
放寬：變得較不嚴(yán)厲或嚴(yán)格
To become less restrained or tense.
放松：變得較不受約束或不緊張

來源：
Middle English relaxen
中古英語 relaxen
from Old French relaxer
源自 古法語 relaxer
from Latin relax3re
源自 拉丁語 relax3re
re- [re-]
re- [前綴re-]
lax3re [to loosen] from laxus [loose] * see slôg-
lax3re [放松] 源自 laxus [松散的] *參見 slôg-

【引伸】
relax.able
adj.（形容詞）