/ ˈlækɪŋ; NAmE / adjective [ not before noun ]
1.
lacking (in sth) having none or not enough of sth :
She's not usually lacking in confidence.
The book is completely lacking in originality.
He was taken on as a teacher but was found lacking (= was thought not to be good enough) .
2.
not present or not available
SYN missing :
I feel there is something lacking in my life.