You can clip, or trim, entities so they end at one or more implied cutting edges defined by other entities. You can also trim entities to the point at which they would intersect an implied cutting edge. To use this tool select 'Trim' from Modify menu bar or select icon from Editig toolbar. By default this option is disable. To make enable you have to select the reference entity.

Steps to Trim  the Entity :

Fig 1

Fig 2

In above fig 1. Entity 'L' is to trimmed by considering the rectangle's edge as boundry edge. The trimmed part of entity 'L' is length (AB). After trimming we will get as shown in fig. 2.

See Also