A Paladin using smite on a non evil target.
I tried something like "You hit but you don't feel the surge of righteous energy in your strike" but that doesn't sound quite right to me.
You strike, but do not strike true.
So I usually try to phrasing things like instead of saying "you failed the Fortitude check" I go something like "You are overwhelmed by the sickening aura".
Ya know give the game a little flair by choosing how I phrase things to keep things sounding interesting.
Thing is tho I am not 100% sure how to word somethings and would like ideas. Things like...
A Paladin using smite on a non evil target.
I tried something like "You hit but you don't feel the surge of righteous energy in your strike" but that doesn't sound quite right to me.
A missed hit where they have a high Armor but a low dodge.
Tried "You manage to land a blow but your blade can not piece his thick hide" (the player got confused by what I meant, if I meant DR or high AC)
Things like that I guess. Just looking for ideas to either use or inspire some creativity.
I don't see anything wrong with your description of Smite Evil to be honest.
Do you have sayings that you use when they miss by a small margin against a person with a shield? I'd go with something like that. "Your attack is deflected by his tough hide which shields him against your blow".
The paladin example seems decent to me.
Remember that paladins get big bonuses to attack, damage, and ignore the DR of certain targets. Another alternative might be "although your weapon normally seems to veer toward your foes and slice through armor like butter, you felt no guidance behind the attack and it glanced impotently off a shoulder-plate that you would have expected to bite through."
Monsters may not have much Dexterity, but they do have it -- a +0, or even a -2, is still more than the -5 that immobile creatures have. If you describe failed attacks purely based on durability, you're going to keep having the problem of 'does my character think that's AC or DR?'. Try to mix them both, with more of an eye toward representing the natural armor bonus.
You could say, for example, "You take advantage of its ponderous movement and stab at its belly. There you find a surprisingly thick hide resisting your strike. Before you can push through, the creature roars in annoyance and swings an arm down, swatting the weapon away from its flesh with terrible strength."
You could also attribute failed attack rolls to luck. Feet can slip against a sandy or wet floor, and the movements of allies might get in the way. However, unless a foe actually has Luck bonuses to AC, don't over-use descriptions that make characters sound foolish, like dropping their weapons and fumbling to pick them up -- it tends to embarrass players who, if they must fail, would prefer to fail heroically than miss like an oaf.
One of the reasons I hate critical failures is because they're almost always described as my character doing something profoundly stupid or clumsy.
Tangling fur and filth could also be great ways to describe natural armor too. "As you lay into the dire boar, your weapon only manages to peel a thick layer of muddy rubbish off its side as it twists out of the blow. Old animal bones, a stray copper piece and other bits of refuse peer out from the exposed area as its beady eyes contort in rage."
Not that I'd be able to come up with that phrasing on the spot, but I'm not against coming to game with some descriptions handy either.