From Ryzom Wiki
Slow Attack is an affliction; a negative status effect that handicaps the target.
It is also known simply as Slow, which is sometimes confusing with the Slow Movement affliction.
A creature under the effect of Slow Attack will perform all their action slower than usual while under the effect. This applies to melee attacks and ranged attacks as well as all magic spell castings. The degree to which they are slowed varies based on what kind of Slow Attack is used.
Slow Attack as spell
Players are able to inflict Slow Attack on a target using the Slow Attack spell from the Offensive Affliction Magic skill. This spell is first available at level 12 magic. Like with all affliction spells, a link must be maintained to keep the target slowed.
Players can increase their chances of resisting a Slow Attack Affliction spell by wearing jewelry that raises their Jungle resistance.
Slow Attack by critical
The Slow Attack caused by a critical hit to the arms is not a magical effect and thus Jungle resistance will not help resist it. Creatures that are immune to Slow Attack spells similarly are not immune to this effect.
Slow Attack as melee ability
Players can inflict yet another type of Slow Attack if they fight with a blunt damage type melee weapon and use the special "Slow Attack" ability, which can only be used with blunt melee weapons. This Slow Attack also lasts a few seconds for every hit.
This also is not a magical effect and thus similarly able to bypass both Jungle resistance and Slow Attack immunity.
Enemies using Slow Attack
Since homin mages are capable of casting Slow Attack affliction spells, it may be used against you in PvP, though it's not very popular there.
Players using maces or staffs may also use the Slow Attack ability for blunt weapons against you in PvP, though again this is not very popular.
Creatures immune to Slow Attack
Slow Attack immunity only applies to the Offensive Affliction spell; not to Slow Attack caused by critical hits or by the blunt weapon special ability.