Rim offset

What does this actually mean? Also if u were to buy a rim w/ the wrong offset... is it even possible to put the rim on ur car or would it just have a funny, unsafe ride? also anybody kno what the offset is for a 90 accord? all i kno is i need a 4x114.3 bolt pattern. I already kno that if i were to try to put on a 4x100 bolt pattern... my wheel wont even go on. just need to kno what offset has to do.

Offset is the distance between the wheels center line & mounting point. Different offest will change the track width of your car - track width: center line from 1 tire to the other. Wider track means better handling. Wrong offset wheels will & will not fit, depending how wrong it is. Slightly wrong will cause tire rubbing. This is why its suggested to purchase wheels for you 90 accord - 38mm-43mm is average & not use too large of tire. Larger/heavier tires & wheels means slow1!
www.whalentire.com tire spec's - speedo change
www.tirerack.com

Using the wrong offset also plays havoc with the suspension geometry of the car.

i have an 04 mitsu. lancer oz w/stock 15 rims (4 lug 4x114.3 w/ 46mm offset on 195/60/15 tires). can i put 17" ADR Intense rims 7-spoke bronze (4/8 lug universal w/ 40mm offset) on 205/40/17 tires on my lancer? will these rims hit my brake caliper w/the 40mm offset on the ADRs?