Yes, you can certainly do that. You can actually do it either at member group level, area level (forum for example), member level, or even at individual topic level.
Group - Edit any group, go to the content tab, switch on "Require approval before content shows?"
Forum - Edit forum. go to posting settings, select the options for "Posts must be approved?"
Member - Edit a member, click edit under warnings & restrictions, change the "Require approval before content shows?" settings
Topic - Click moderator actions, select "Enable post approval"