smackheadsmack‧head /ˈsmækhed/ noun [countable] informal 
someone who uses the drug heroin
someone who uses the drug heroin- second screener
- second screening
- second sight
- second-string
- Second World War
- secrecy
- secret
- secret agent
- secretarial
- Secretariat
- secretariat
- secretary
- secretary general
- Secretary of State
- secret ballot
- secrete
- secretion
- secretive
- secretively
- secretiveness
- secretly
- secret police
- secret service
- sect
- sectarian