Wordweb v5.2 - free offline english dictionary and thesaurus

i use this dictionary on my desktop as it is free, has less memory footprint, and it can lookup words from any program.

http://wordweb.info/free/

WordWeb is a one-click English thesaurus and dictionary for Windows that can look up words from in almost any program. It works off-line, but can also look up words in web references such as the Wikipedia encyclopedia. Features of the free version include:

Definitions and synonyms
Proper nouns
Related words
Pronunciations

150 000 root words
120 000 synonym sets
Look up words in almost any program

NOTE: according to the licensing agreement, you can use it for free only if you take at most two commercial flights in a year :-P
seriously it is not a joke. have a look at this link for verification
http://wordweb.info/free/licence5.html