An example of a supine action is someone lying on her back.
An example of a supine reaction is not caring when someone is injured.
Origin of supine
- Middle English supin Latin verbal noun from Late Latin supīnum (verbum) (verb) lying on its back, (verb) going back neuter of Latin supīnus upo in Indo-European roots
From American Heritage Dictionary of the English Language, 5th Edition
- From Middle English supin, from Latin supinum, supinus. Grammatical meaning is from the phrase supinum verbum.