a lost child还是a losing child?

a lost child=a missing child

lost
[lCst]
adj.
失去的, 丧失的, 错过的, 迷惑的, 不为人知的
vbl.
lose的过去式和过去分词

lost
lost
AHD:[lôst, l¼st]
D.J.[l%8st, l%st]
K.K.[l%st, l$st]
v.（动词）
Past tense and past participle of lose
lose的过去式和过去分词
adj.（形容词）
Unable to find one's way:
迷路的：无法找到某人的路的：
a lost child.
一个迷路的孩子
No longer in the possession, care, or control of someone or something:
丢失的：不再拥有、照顾或支配某人或某物的：
a lost pen.
一只丢失的钢笔
No longer known or practiced:
不再为人所知或实践的：
a lost art.
一门失传的艺术
Unable to function, act, or make progress.
不产生效果的：不能再作用、行动或进步的
Spiritually or physically destroyed.
无感觉的，麻木的：精神上或肉体上被摧毁的
Completely involved or absorbed; rapt:
沉湎其中的：完全参与或投入的；着迷的：
lost in thought.
陷入思考

missing
[5misiN]
adj.
不见的, 缺少的

missing
miss.ing
AHD:[m¹s“¹ng]
D.J