耳闻 literally means 'ear-hear' — combining 耳 (ear) and 闻 (to hear, to smell), it emphasizes hearing something directly through one’s ears. Though 闻 can also mean 'to smell', in this compound it exclusively means 'to hear'. 耳闻 functions primarily as a noun meaning 'firsthand report' or 'what one has heard', often contrasted with 目睹 ('to witness with one’s eyes'). It frequently appears in formal or literary contexts, especially in the paired phrase 耳闻目睹 ('hear and see for oneself'), indicating direct personal experience.

The term carries a nuance of reliability: 耳闻 suggests information acquired audibly but not necessarily verified visually — so it may imply hearsay unless paired with other evidence. It is rarely used alone in casual speech; instead, it appears in set phrases, written reports, or rhetorical expressions assessing credibility of information. Learners should note that while it looks like a verb, its standalone use is nominal and often abstract — e.g., 'based on mere 耳闻' implies unconfirmed rumor.