1. [n]  vehicle equipped with heavy wide smooth rollers for compacting roads and pavements
2. [n]  a massive inexorable force that seems to crush everything in its way
3. [v]  overwhelm by using great force; "steamroller the opposition"
4. [v]  crush with a steamroller as if to level; "steamroller the road"
5. [v]  proceed with great force; "The new teacher tends to steamroller"
6. [v]  bring to a specified state by overwhelming force or pressure; "The Senator steamrollered the bill to defeat"

STEAMROLLER is a 11 letter word that starts with S.