What openings are closed and defensive? Which openings would be regarded as leading to a closed position and being defensive?  Specifically, openings that would be drawish, even against stronger players, but there is still always a possibility of squeezing out a win if played carefully and the opponent goes wrong.
The openings which are considered more drawish are usually openings where you have no central tension and symmetric pawn structure, something like the exchange French/Slav.  It's asymmetry and tension that gives room for complications.  I can't think of many huddled, solid defensive lines where the goal is just to be closed and impenetrable, though you could argue a tamely played and unambitious Stonewall, Colle, or London could fit the bill.  Still, by playing this way, you are creating an imbalance in space and activity which isn't in your favor.  Not recommended.