Yep. I mean lie.
I appreciate 1AJs rescue, but I make no distinction b/t lying by omission and an outright lie. The only difference is who you are lying to.
I just think its classier to avoid the question by 'keeping one's mouth shut'. I think that disclosing the amount of prior partners too early in a relationship is asking for trouble.
If any guy I was dating was so crude as to ask me that number before we had been seeing each other exclusively for at least a few months I would deliberately inflate that number to the point I would scare him off. His losing me in the process, would be his punishment for his stupidity.
But I have a very high opinion of myself.
Seriously, by the same token, I think the converse is true for females asking guys. Its none of their business. If you are uncertain about sleeping with someone, say for fear of an STD, then you shouldn't be with them. Or you should both get tested. The number is irrelevant. A woman could have been married to the same man, faithful, for 20 years & still end up with an STD if the guy cheated on her w/o her knowledge.
Its all about judgement of that particular person at that particular time.