Let me try and give an example that I hope does not totally confuse you, but first, a brief explanation of validity.

According to the Church, a Sacrament is valid when there is valid FORM, MATTER and INTENT.

FORM means the WORDS USED.

MATTER means whatever THING is being used (in the case of a Baptism, it's water. In the case of a Mass, it's unleavened wheaten bread and wine mixed with water).

INTENT means that the person performing the act MEANS TO DO WHAT THE CHURCH MEANS TO DO, BY HER DOGMATIC DEFINITIONS OF WHAT MUST BE DONE.

Here's my (probably poor) example:

Let's say you need to get to my house from point A. If I tell you the WRONG TURNS, it's INVALID, because it can't do what NEEDS to be done. If, however, I tell you the RIGHT TURNS but the wrong STREET NAMES, you CAN still get there if you ONLY follow the TURNS and not get confused by the NAMES. In that case, the FORM is ILLICIT because there's a GOOD CHANCE that you'll get lost with the WRONG STREET NAMES, even if the TURNS are correct.

MATTER, in my example, would be like telling you to go to my house by sitting on a milk-crate and expecting it to fly, or by giving you a rusty, wobbly bike. The first is INVALID because what you need can't be accomplished. The second, again, is ILLICIT, because it is a gravely POOR way to travel, but it is not INVALID, because it is still at least POSSIBLE to get to my house on that bike without killing yourself.

INTENT, of course, means that I MUST REALLY INTEND to get you to my house. Not to someone ELSE'S house, and not CLOSE to my house, but to the house where I actually LIVE. If I CHANGE those street-names AND give you a rusty bike, you COULD still make it, but the question of whether I really MEAN for you to actually GET THERE must be raised if one is to be honest.

The Novus Ordo 'service' CHANGED not only the Words of the Consecration, but also phrases THROUGHOUT the text, making the FORM questionable, because it is not ABSOLUTELY CLEAR from the FORM that what we are talking about is the Roman Catholic Sacrifice of the Mass.

The MATTER is USUALLY not changed, but MANY, MANY Newpriests and Newbishops have used INVALID matter, even going so far as to use SODA POP and SNACK CHIPS as 'matter'. No, really... I'm totally serious.

When you add together a TON of QUESTIONABLE FORM and no real INSISTENCE upon proper MATTER (because otherwise the people responsible for the chips/soda would have been censored or even excommunicated for blasphemy and sacrilege), you get a SERIOUS, DEEP and LEGITIMATE DOUBT of the INTENT of the 'celebrant' of the service.

INVALID? I believe so personally, because I do not believe the Words of the Consecration can be changed or altered validly. I MAY be legally incorrect, but I know there is a case to be made for invalidity.

ILLICIT? ABSOLUTELY, and anything that does not point DIRECTLY and PLAINLY to Roman Catholic Truth and Faith without ambiguity is to be AVOIDED AT ALL COSTS.

There has NEVER been a sacrament, prayer or devotion accepted by or promulgated by the Church that has EVER been this ambiguous and vague when it comes to a clear presentation of Catholic teaching.

I hope this helped, even a little.

Immaculate Heart of Mary, triumph soon.

Sacred Heart of Jesus, have mercy on us.

thank you both for your very good and clear descriptions. it is much appreciated.  

o.k. i have seen this terminology come up alot for NO.

I looked up the definitions to make sure i wasn't losing it...

please and I mean this sincerely, how can this statement be justified, as the definition basically cancel each other out to zip in meaning.

You are correcting when having the Catholic Church in mind, as she could never act illicitly or foster any illicit practices. Otherwise, we would never be sure if we please God.

Translation: "Valid but naughty"

If one finds the authority of many bishops dubious in the first place, such naughtiness becomes less of a concern to anyone serious about the Faith.