a.

1. 體弱的；（因年邁而）衰弱的
   Great-grandmother was old and infirm.

   曾祖母年邁體弱。

2. 意志薄弱的；不堅定的；優柔寡斷的
   Hunter is infirm of purpose.

   亨特為人優柔寡斷。

3. （構造物）不穩固的，動搖的
4. 不牢靠的；不生效的
   an infirm title to property

   不牢靠的產權

adj.

1. not physically strong, especially through age.
2. archaic irresolute; weak.