Subconscious means happening in the mind below awareness. A subconscious habit, subconscious bias, the subconscious mind.
As a noun with the, the subconscious means that part of the mind. It is a popular word rather than a technical one — Freud used the unconscious and specifically objected to subconscious — so in clinical writing you will find unconscious instead. Note subconsciously, which is very common; and that both words describe the same idea of mental activity you cannot inspect from inside.
1adjectivesubconsciousHappening in the mind below awareness.
“Her fear of water may come from a subconscious memory of her childhood.”
2nounmindThe part of the mind below awareness.
“The whole theory rests on what the subconscious is doing.”
Too few real examples of this word to estimate which sense is commonest.
subconscious is a level of the mind.
Latin
cōnscius — conscious, conscious of guilt
English
conscious
English, today
subconscious
Built from
From sub + conscious. conscious 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