He will visit an invalid.他将要去看望一个病人。
Her grandfather is an invalid.她的祖父是一个残疾人。

invalid, case, patient
参见patient条。

用作定语
▲～+n.
This is an invalid assumption.这是一个无根据的假设。
He had to look after his invalid brother.他不得不照看他有病的弟弟。
用作表语
▲S+be+～
Their marriage is invalid.他们的婚姻是无效的。