"looking up words in their database isn't something you would be able to do
in your computer."
The premise in this statement is that we want to do the task with a server.
That premise affects the answer ("yes, we can only look up a word on a
server, if we use a server).
I don't think that we need a server to look up words in a dictionary [1]. If
remote dictionaries have a legitimate use, maybe the dictionary could offer
options: to download dictionaries, or to use a server.
If Trisquel won't come with definition files, the server option may be worth
keeping for people who have low-bandwidth Internet connections.
[1] Here's a dictionary application that doesn't depend on a server each
search:
https://code.google.com/p/quickdic-dictionary/
