Hold Shift and move your mouse over any word to see its definition instantly in a small popup — no click needed. This works for both English and Japanese, and is purely a preview: hovering doesn't track the word or affect its count. Click + Track inside the popup if you want to track what you're previewing.

• Toggle this on/off anytime in Options → Learning Settings, in case Shift+hover ever conflicts with another extension or site.
• Only resolves single words — for multi-word idioms, right-click a manual selection as before.
• Japanese detection uses a longest-match approach against Jisho (no bundled dictionary), so extremely long compound words may only match their first 8 characters.