meaning of coldfront weather?

Answer 1

Cold air being heavier than warm air, a vertical cross-section of a cold front shows a wedge of cold air undercutting the warm air ahead of it. This pushes up moist surface air in the warm air, and moisture condenses, giving clouds, rain and wind gusts. Also, isobars tighten near a cold front so winds pick up as it approaches. As it passes, winds ease and temperatures fall as cool polar air replaces the warm flow ahead of the front. The barometer falls as the front approaches then rises again after it has passed.

Answer 2

Since fronts are just the boundary between two air masses of differing densities (and thus, differing temperatures), with a cold front you've got a cool air mass replacing a warm one.
To skip the technical meterology of a front:
In the summer you may have cooler temperatures as it passes, but more noticably it will bring drier air, relief from humidity. You may also have thunderstorms or squall lines along and ahead of the front, but not all cold fronts bring tons of precip, however some can bring days of precip.
Winter is when you'll see cold fronts bring much colder air and snowstorms.
The weather after a front passes generally clears up, sometimes slowly with clouds lingering, and sometimes fairly quick.