First of all, I don't believe that it violates copyright in any way to loan a pattern to a friend, unless you know or strongly suspect that she will be copying the pattern.

Is your concern that this lady won't return the pattern? Or that she will copy it? Or just that you don't want to share what you have purchased with someone who is clearly wanting a freebie? Any of these are legitimate concerns, but you need to be clear with yourself about what is your cause for concern.

I would not lie, not make excuses, just tell her that you don't loan patterns because (you are afraid of not getting them back; you do not want them copied because of copyright concerns; you paid for it with good money and you expect others should do the same). Pick your response and stick to it. It is not something to be ashamed of, but something that is true and worth protecting.

It is best to be honest as to why you don't want her to have the pattern as further down the track you risk being caught out in a lie

I'd do this. Keeping the pattern in a safe place at home. Patterns cost money and have copyright on and surely some infringement must be taking place when people borrow/ lend/ keep.

i don't see any reason to make up a reason you "can't" lend her the pattern.
just say no.
politely, but firmly.
if she presses for a reason tell her the truth.
you don't want to.

nothing in the world wrong with that.

I fully agree with dunster on this. IMO honesty is always best on the long run, don't be tempted to "create" excuses!

I agree, that the "I am making another one and then my daughter has dibs on the pattern next" is the appropriate answer. I would certainly tell her the name of the pattern and where she might buy her own. I have told my friends that I NEVER loan out my Bargello books.

Years ago I loaned a pattern to a friend. She moved out of state taking pattern with her, and I never heard from her again. Don't loan if it's a pattern you may use again.

Remember Nancy Reagan? "Just say NO!"

I totally agree with Patrice...why make up a reason?

Just tell her you don't lend out your patterns, period. Tell her what the pattern name is and suggest where to get it and then walk away knowing you don't have to ever worry about what 'story' you told her. Nothing is simpler to remember than the truth.

I too would just say "no, I don't lend out my patterns, (or any of my stuff)". Which is true for us here. We get asked to "borrow" the Dyson, or "borrow" the rug shampoo-er. We have learned to say "no, we don't lend out anything, and we don't borrow anything either". So far no one has gotten upset with that answer. It's the truth too.