Phrase used to describe a person or situation which is either less than desirable or lacklustre. May also be used to comment on the attitude or action of a person.
"How was your trip to Guernsey?"
"Terrible, it was lacking in salt"
"I can't make it, you go on without me!!"
"Your attitude is sorely lacking in salt, stand up soldier!"
"Hai lets go to simon's party"
"No wai, it's gonna totally lack salt"