If you want to get a quick word translation, ImTranslator offers you a few ways to do so.
Word Translation with a Shortcut
Hold the ALT key while highlighting a word. The Pop-up window opens with the word translation.
Word Translation without a Shortcut
Highlight a word with the mouse and you will see an instant translation of a word without pressing or holding any key.
To enable this mode, remove the Shortcuts from the Pop-up Bubble Options by clicking on X sign, and then Save Options.
To access Options right-click on the ImTranslator button on the Chrome toolbar and select Options.
Note: This translation mode is not recommended because it may interfere with other tasks where you make text selection with the mouse.
Word Translation on Double-click
You can also get a quick word translation by using the "Translate on double-click" feature.
Simply double-click on the word you want to see the translation, and the Pop-up window with available translations opens instantly.
To enable this feature go to the Pop-up Bubble Options and check mark the option "Translate on double-click".
Don't forget the Save options to record your changes.