Someone involved in criminal act and in violation of US immigration Laws. The Offence could be in any country. The inadmissibility could be temporary or permanent.
It means that you are not allowed to enter United States of America since you were charged or been arrested or convicted of an offence inside or outside of United States of America. If you are trying to enter the USA as a nonimmigrant on a temporary visit, in that case you need visa to enter USA (unless you are exempted).
If you are a Canadian Citizen and are inadmissible and intending to visit USA then majority of time you are required to apply for Advance permission to enter United States of America. The application form is I192. You may invariably fall into this category.
Therefor, you are being a Canadian Citizen although exempted for USA visa, but you may be denied entry to USA due to inadmissibility.
NOTE: Grant of US Waiver I192 is not a travel document. Any foreign citizen other then Canadian or any national who need a visa for USA is required to obtain a valid visa for USA separately.
We will get RCMP Certified Criminal Check Report by way of submitting your fingerprints to RCMP. We are RCMP Accredited fingerprinting agency.
There could be more to the list depends on each individual situation.