A bewildering array of on-screen dictionary utilities, many with equally bewilderingly similar names, are available for Linux. Most are geared unashamedly to casual users, and in their simplest form are little more than a nice input box linked to a two-column word list.
As CAT tools have developed over the two decades since this site was first created, they have increasingly included the functionality to access external dictionaries from within the CAT tool. Besides the content of the dictionaries themselves, compatibility between the CAT tool and the dictionary application or file format is likely to be the main factor determining their suitability.