General synonyms:
* Missed
* Wanted
* Needed
* Desired
* Was without
* Was deficient in
* Was short of
* Was deprived of
More specific synonyms:
* Absent (when referring to a physical object or quality)
* Insufficient (when referring to a quantity)
* Deficient (when referring to a quality or ability)
* Missing (when referring to something that is lost)
* Without (when referring to a lack of something specific)
* Deprived (when referring to a lack of something essential)
The best synonym for "lacked" will depend on the specific context of your sentence.