Although intended for ESL students, this guide also points to general sources on English usage, which are useful for all of us.
Last Updated: Nov 19, 2015
"Activeds.com is a web based free English Chinese/Chinese-English online dictionary." Although this site is intended primarily for English speakers learning Chinese, it can also be used by "Chinese native with advanced English" skills. (Accuracy has not be tested.)
- ECTACO English - Arabic Online Dictionary
This commercial website offers a limited version of its online dictionary for free. The full version requires purchase. (Accuracy has not be tested.)