Oppugno - When You're too Lazy to Attack Them Directly.
Oppugno itself is a fairly well known jinx though, personally, I would classify it more as an augment as it's infinitely more useful when attached to spells that conjure or produce their own physical objects, but that's not my department and not my call to make--as unfortunate as that is. I imagine it earned its "jinx" classification due to the fact that it works on objects (conjured or otherwise) as well as on sentient, near-sentient, and non-sentient beings. Not to mention, if you forget to target something that is meant to be flung or ordered to attack, it doesn't actually do anything and you look a bit daft.
As it stands, Oppugno is classified as a jinx, most commonly used to pick up and fling an object at a target. That, however, is a very basic view of the spell's overall capabilities. Yes, it can be useful simply to throw an object (let's be honest, if you're using this on an inanimate object, chances are you have no idea what it does) or objects at something, or to create a bit of chaos by setting multiple objects flying around at nothing in particular, but that is something any child could manage and shows a distinct lack of finesse and refinement in its use.
Used properly, and on the correct things, Oppugno will cause whatever it is cast at or attached to to attack the target, rather than simply be flung at it. If you just want to throw something at someone else, pick it up and throw it, or use a more suitable spell.
This does work with some sorts of inanimate objects, but depending on what they are, it can be wholly ineffective or just irritating.
Used properly and with a good choice of object or being, it can be easily lethal; in terms of objects, the most appropriate would be sharp, jagged, hard, or difficult to catch, and be used on multiple pieces of said object. Instead of flinging a wine glass at someone's face, for example, it would be more effective to smash the glass into thousands of shards, then throw those instead; much more difficult to dodge and block, and a higher chance of causing some damage.
It can similarly be used with swarms of--really anything, anything that swarms; wasps and pixies immediately come to mind, and both could cause a significant amount of damage to a target, especially Cornish pixies.
Oppugno affects conjured objects and beings in the same manner as it does those that physically exist.
Using Oppugno on a sentient being, for example a person, is firstly not recommended as it's not strictly legal, but secondly, due to the fact that it's rather difficult.
In order for it to be successful, the caster of the jinx needs to be sufficiently powerful to make the jinx able to overtake the target's will. This is not nearly as easy as it may sound, and it requires the caster maintain that level of control, which is equally difficult as many times a sentient target will resist or attempt to actively fight back.
While keeping hold of the target, the caster is left somewhat vulnerable, as the majority of their focus must stay on keeping their own target controlled. If the caster is interrupted, Oppugno's hold over its sentient target will be interrupted.
I have seen this attempted numerous times, and have never seen it end with anything I'd consider success; even if the caster is able to control the target, they are then easy to interrupt.
There are more suitable curses--though those tend to be considered a bit on the Unforgivable side of things--for controlling a target and making it do as you wish. That, or you can simply convince them without the use of magic that they ought to be assisting you for one reason or another.
Semi-sentient or near sentient beings may also attempt to fight back, and can be difficult to control as well; therefore, it is recommended that one avoid attempting to use Oppugno  on such creatures. Many, once they break free, will be livid with the caster, and will likely turn on them immediately.
Strangely, Oppugno appears to be highly effective on dogs; this may stem from the dog's domestication and the species' overall willingness to go along with what it considers its social group. It's possible it would be just as effective on other social, non-sentient animals.
Flocking birds seem most obvious, but I have only ever attempted (or seen attempted) Oppugno  with birds conjured via Avis, and those are not actual birds so much as they are magical constructs.
Oppugno can also be woven into wards (existing or new), typically as a trigger spell that will cause a cascading effect of other wards going off, though it can also be attached to physical objects around or inside of existing warding, causing said objects to 'attack' whoever misses removing the Oppugno from the wards while attempting to get in. When Oppugno is attached to an object, it also must be chained with a triggering type of ward so that if the trigger is tripped, Oppugno  will activate, and cause the object(s) to attack as desired.
The addition of extra targeting or seeking augments is recommended in that case as, unless you know exactly who or what will try to get through your wards, Oppugno may inadvertently 'choose' the wrong target when set off as part of a failed attempt to break through warding.
Because of the complexity involved, Oppugno is not often used in ward chains, a reason for which it is all the more necessary to sweep for its presence.