The absence of something; a lack.
"The report was criticized for its complete lack of evidence regarding the incident."
"The lack of rain caused severe drought in the valley."
Usage: Use the noun form lacking to mean an instance of missing something, though it is often stylistically replaced by "lack" in modern English. Avoid using this as a standalone subject when referring to general scarcity, where "a lack" or simply "the absence" may be clearer.
present participle of lack
"The empty wallet was lacking funds, forcing us to cancel our dinner reservation."
In plain English: To lack something means to not have it at all.
"The new policy is lacking in clear guidelines for employees to follow."
Missing or not having enough of (a good quality, etc).
"The proposal was rejected because it lacked any concrete plan for reducing emissions."
In plain English: Lacking means not having enough of something you need or want.
"The package arrived lacking any instructions on how to assemble it."