We don't have synonyms for lock-down yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are low-down, lookdown and lock down.
(n) :
Alternative form of lockdown. [The confinement of people in their own rooms (e.g., in a school) or cells (in a prison), or to their own homes or areas (e.g., in the case of a city- or nation-wide issue) as a security measure after or amid a disturbance or as a non-pharmaceutical intervention in a pandemic.]
(n) :
Alternative form of lockdown. [The confinement of people in their own rooms (e.g., in a school) or cells (in a prison), or to their own homes or areas (e.g., in the case of a city- or nation-wide issue) as a security measure after or amid a disturbance or as a non-pharmaceutical intervention in a pandemic.]