When does a word clearly mean its opposite?

For me, every time somebody describes their website as "secure" or their "secure login process". For me, this communicates as loudly and clearly as possible that they don't know the first thing about security.

No system is ever secure. The best we can do is: a probability of security against a specific enumerated set of attacks. It's never 100%, and we have no idea about potential attacks we haven't thought of.