Tight stops simply refer to a stop loss that is placed quite close to your entry price.
If you purchased a stock at $1, a tight stop might be .95c, whereas generally you might allow for a bit more leeway and place the stop somewhere between .75c and .80c
As your relatively new, I strongly recommend you going to this site
http://iitm.com/Site-Map.htm
and reading the section under 'Tharp Concepts' especially the one on risk management/position sizing. It is must know information if you want to trade or invest profitably