The difference is the rules for BOTH contestants: semi-contact means you don't hit hard. Full contact means anything up to and including KO is allowed.
It is not correct to say "you are full contact" and "your partner is semi-contact".
You both fight as hard as the rules allow. If you prefer full-contact fighting, then, you should not be fighting in semi-contact matches. If you did this, and you fought too hard, you can get DQ'ed.
Most reasonably conditioned people can take semi contact blows with the exception of very few targets such as the nose maybe. Taking full contact blows is a different matter entirely if your techniques are halfway decent. Of course if your techniques are sports techniques where your punches are pulled, no matter how full contact you go you are not going to get much reaction from your opponent either.
Bottom line as it is with all these questions, depends on the practitioner(s).
Whats the difference between semi contact kickboxing and full contact. If I was full contact and my opponent was semi who would win an why
