noun
second-hand knowledge; hearsay; pick-up knowledge
Knowledge acquired by hearing others talk, not through formal study or direct experience. Often carries a slightly dismissive nuance, implying superficial or unreliable learning.
彼の知識は耳学問に過ぎない。
His knowledge is nothing more than hearsay.
耳学問で得た
Information gained through second-hand knowledge is often unreliable.