Glosbe - Huge collaborative massively multilingual dictionary.
GoldenDict - The program has the following features: Use of WebKit for an accurate articles' representation, complete with all formatting, colors, images and links.
Visuwords - The fun and free way to look up definitions. THE graphical dictionary and visual thesaurus.
Google Translate - Google's free service instantly translates words, phrases, and web pages between English and over 100 other languages.
Wordnik - the biggest online English dictionary, by number of words
DeepL Translator - DeepL Translator is a machine translator that currently supports 42 language combinations.