Final answer:
The etymological meaning of 'preposterous' is true and it originates from the Latin words 'prae' meaning 'before' and 'posterus' meaning 'coming after.'
Step-by-step explanation:
The etymological meaning of preposterous is indeed "having the back part before [the rest]." The word comes from the Latin praeposterus, with prae meaning 'before' and posterus meaning 'coming after.' Therefore, the statement that the etymological meaning of preposterous is "having the back part before [the rest]" is true.