build up
phrasal verbbuild up (to something)  
- to become greater, more powerful or larger in number
- All the pressure built up and he was off work for weeks with stress.
 - The music builds up to a rousing climax.
 
 
build somebody/something up 
- [usually passive] to give a very positive and enthusiastic description of somebody/something, often making them seem better than they really are
- The play was built up to be a masterpiece but I found it very disappointing.
 
 
build somebody/yourself  up 
- to make somebody/yourself healthier or stronger
- You need more protein to build you up.
 
 
build something  up 
- to create or develop something
- She's built up a very successful business.
 - These finds help us build up a picture of life in the Middle Ages.
 - I am anxious not to build up false hopes (= to encourage people to hope for too much).
 - The gallery has built up a fine collection of contemporary art.
 - We’ve built up good relationships with our clients.
 
 - to make something higher or stronger than it was before
- The sea defences have been built up to ensure that such a disaster will not strike again.