All investments carry some kind of risk and mutual funds are no exception. Mutual funds are just a basket of investments that contain things like equities (stocks), government or corporate bonds, money market, indices (TSX 60), etc. What's inside the funds determines the relative level of risk i.e funds containing 100% stocks would be relatively riskier than funds containing 100% bonds.
I would say that all investments are risky if you do not understand how they work, the costs of holding them (all funds have management fees) and what is inside them. There are many reasons for and against investing in any stock, bond, or fund. It just depends on what your objective is.
A good website for financial terminology is
www.getsmarteraboutmoney.ca. They clearly describe how all the various financial products work.