Parrying

Related:
* Blocking
* Target lock - may sometimes require target lock (for whose attacks you're parrying)
* Dodging
* Counter attacks
* Melee weapons

Parrying redirects attacks rather than outright blocking them. Blocking with swords or most any other weapon for one is highly discouraged by anyone who knows one bit about fencing. Oddly parrying is not commonly seen in games, movies or any other animated or live action visual art (they err to block instead).

If sound is the only cue on what is happening, then a loud clanging is quite sure indication of blocking while metal sliding on metal without much of a clang would be sign of a somewhat proper parry (though there are surely other ways).

However, since this reduces the chances of loud noises, flashy spark effects and so forth, they aren't exactly favoured by those into creating entertainment.