noun which may take the genitive case particle 'no', noun
sharp-eared; quick to hear news
Describes someone who is quick to catch rumors, news, or information. Often used in the phrase 早耳な人 (a person with sharp ears).
彼は早耳で、会社の噂をすぐに聞きつける。
He is sharp-eared and quickly picks up on office rumors.
早耳な友達が、新製品の情報を教えてくれた。
My quick-eared friend told me about the new product.
A common phrase meaning 'to be quick to hear news'. 早耳 is a noun/adjectival noun form of the same concept.
Compound of 早 (はや, 'quick') + 耳 (みみ, 'ear'). The exact historical derivation is uncertain, but the meaning is transparent from its components.