Conscious means awake and able to notice the world. Still conscious, regain consciousness, conscious throughout.
In medicine it is a clinical state, and losing consciousness is the boundary that matters. The second sense is done on purpose: a conscious decision, a conscious effort — which is the commoner use in ordinary speech. Conscious of means aware of: conscious of the risk, self-conscious. Note conscience, which is the moral sense and a different word, and conscientious, which means careful and thorough.
1adjectiveawakeAwake and able to notice the world.
“He was conscious the whole time and remembers none of it.”
2adjectivedoneDone on purpose.
“It was a conscious decision and a bad one.”
3adjectiveawareAware of something.
“She was conscious of the risk and took it anyway.”
conscious is a state of awareness.
Latin conscius means knowing with — con-, with, plus scire, to know. Conscious and conscience are the same word, one about knowing the world and one about knowing what you did.
Latin
cōnscius — conscious, conscious of guilt
English, today
conscious
Built from
First use appears c. 1573 in the sense of "aware of wrongdoing".[https://web.archive.org/web/20220714064352/https://www.lexico.com/definition/conscious] From Latin cōnscius (“conscious, conscious of guilt”), itself from con- (a form of com- (“together”)) + scio (“to know”) + -us.
Etymology from Wiktionary, CC BY-SA