noun
learning by heart; memorization
Refers to committing something to memory, often through repetition. Can imply rote learning.
英単語を空覚えするのは効率が悪い。
Memorizing English words by rote is inefficient.
彼は教科書を空覚えして試験に臨んだ。
He memorized the textbook and took the exam.
noun
faint memory; vague recollection
Used when one has only a dim or uncertain memory of something. Often contrasted with うろ覚え, which implies a hazy or unreliable memory.
See also: うろ覚え
その話は空覚えしかない。
I have only a faint memory of that story.
空覚えで答えたら、間違っていた。
I answered from a vague recollection and got it wrong.
うろ覚え means a hazy, unreliable memory, while 空覚え can mean either memorization or a faint memory. In the 'faint memory' sense, 空覚え is less common and may be considered a variant of うろ覚え.
暗記 is the standard word for memorization. 空覚え is less common and may carry a nuance of rote or mechanical memorization.
Compound of 空 (そら, 'empty, sky') and 覚え (おぼえ, 'memory, learning'). The exact semantic development is uncertain; 空 may imply 'by heart' (as if from the air) or 'vague' (as in empty/insubstantial).