build up
US /bɪld ʌp/
UK /bɪld ʌp/

1.
renforcer, développer, accumuler
to increase or strengthen something gradually
:
•
She needs to build up her strength after the illness.
Elle doit renforcer sa force après la maladie.
•
The company managed to build up a good reputation over the years.
L'entreprise a réussi à se forger une bonne réputation au fil des ans.
2.
faire mousser, exagérer, louer
to praise someone or something in an exaggerated way, often to increase their importance or value
:
•
The media tried to build up the new celebrity.
Les médias ont essayé de faire mousser la nouvelle célébrité.
•
Don't build up your hopes too much.
Ne monte pas trop tes espoirs.