What does "technical fighting game" mean?

Does it mean “high execution demanding” (strict timing and fast strings of input) or “deep understanding of the mechanics/characters”?
And why do people use the word ‘technical’ instead of ‘execution’ or ‘knowledge’?

Maybe it would be easier if you gave a context?

Not knowing context, it generally refers to one of two things:

  1. Highly execution demanding fighting game
  2. “Traditional” fighting game, ie 2d plain, 1 player versus 1 player. In the vein of streetfighter or airdash games.
    there are also of course 3D games that have the same basic aspects, like tekken or soul calibur.

Non traditional would be games like smash or senko no ronde.

Alpha 3

Out of context I would say any game that has “turns”. A game without any real your turn my turn wouldn’t be technical at all.

A lot of (hidden) mechanics and options.

Divekick

A game with a metagame, like MvC2 for example.