The phrase "case out" can have various meanings depending on the context. It can refer to casing out a place for security purposes or to examine it thoroughly. In these instances, synonyms for "case out" include inspect, examine, scrutinize, survey, and reconnoiter.
On the other hand, "case out" can also mean to plan or prepare for a particular situation or event. Some synonyms for this meaning are strategize, plan, scheme, plot, and prepare.
Lastly, "case out" can be slang for checking out a person in an attractive or suspicious manner. Some synonyms for this slang usage are eyeing, scoping out, checking out, and sizing up.
Overall, the varied meanings and contexts in which "case out" can be used make it important to use proper synonyms that convey the intended message accurately.