In other words: Old, Aged, Mature, Former, Ancient, Past, Historic, Bygone, Preceding…
To be at a lose for words, is to be in need of a Thesaurus.
As a writer, I often use a Thesaurus to minimize the use of the same word again and again, so that my writing is more interesting and readable. Imagine if the only word ever used to describe a project was the word "project". Boring. Here's a list of optional words that you can use in place of "project" to enhance your writing:
Obviously, when exchanging the word "project" with any one of the above options you must decide whether or not the word makes sense in relation to your story or subject. I have also found that the more I use a Thesaurus in my writing, the more I can come up with a variety of options on my own.
Another example of how a Thesaurus comes in handy, is understanding the actual definition of a word and how it can apply to your writing. Re-read January's Tip Of The Month and you'll understand what I mean. (You'll have to read it for yourself. I don't want to give it away.)
The bottom line: With all of the new technology we have today, sometimes using the tools of the past are still the best method.