behind

noun:the rear part of something; the back side
- The vase fell off the table and cracked against the behind of the sofa.
noun:the part of the body that is opposite to the front; the backside
- She patted the horse on its behind.
verb:to support, endorse, or advocate for someone or something
- The whole team is behind you on this decision.
preposition:at the root of; causing; responsible for
- What was the reason behind his sudden resignation?
noun:a state of being late or delayed, especially with tasks, payments, or schedules
- He's always in behind with his rent, which worries his landlord.
adverb:later than someone else in a race, competition, or sequence
- He finished the marathon behind the leading pack but ahead of most participants.