形容詞 lax:

1. lacking in rigor or strictness
   同義詞：slack
2. pronounced with muscles of the tongue and jaw relatively relaxed (e.g., the vowel sound in `bet')
3. not taut or rigid; not stretched or held tight
4. lacking in strength or firmness or resilience
   同義詞：flaccid, limp, slack
5. emptying easily or excessively
   同義詞：loose

lax

adj.（形容詞）
lax.er,lax.est
Lacking in rigor, strictness, or firmness.See Synonyms at negligent
不嚴格的：缺少精力的、不嚴格或不結(jié)實的參見 negligent
Not taut, firm, or compact; slack.See Synonyms at loose
松弛的：不緊、不嚴密或不堅實的；放松的參見 loose
Loose and not easily retained or controlled. Used of bowel movements.
不易控制的：松弛的并且不容易保持或控制的。用于排便
Linguistics Pronounced with the muscles of the tongue and jaw relatively relaxed, as the vowele in let.
【語言學】 松弛元音的：舌頭和下顎肌肉比較放松時發(fā)出的，如元音e 在 let 中的發(fā)音

來源：
Middle English
中古英語
from Latin laxus [loose, lax] * see slôg-
源自 拉丁語 laxus [松的，松懈的] *參見 slôg-

【引伸】
laxa.tion
n.（名詞）
lax.ly
adv.（副詞）
lax.ness
n.（名詞）