Honest and accurate information must always be disclosed when applying for any Canadian immigration or visa program. Not disclosing relevant details, such as an earlier refusal of your application could lead to serious repercussions for this application, such as rejection, inadmissibility into Canada, or legal implications.
When applying for a study visa, you will be asked for information regarding your immigration history – including any previous applications and refusals. If any previous refusals go undeclared in your current application, an immigration officer reviewing your file could discover this during their background checks and potentially deny you permission.
If this occurs, your application could be denied and barred from entering Canada for a specified timeframe. Furthermore, further scrutiny from immigration authorities may increase, further complicating future attempts to travel or immigrate to Canada.
Honest and open communication in your application is highly encouraged, even if a prior refusal could negatively impact it. Simply provide an explanation for it while showing how your current circumstances have evolved to address any potential concerns that led to the refusal in the past.