weak·en 
/ˈwi:kən/ verb
weak·ens; weak·ened; weak·en·ing /ˈwi:kən/ verb 1 [+ obj] : to make (something or someone) weaker, less forceful, less effective, etc.
▪ The disease weakens the immune system. ▪ people (whose bodies are) weakened by hunger ▪ Some are concerned that the increase in taxes will weaken the economy. ▪ The beams had been weakened by water damage. ▪ efforts to weaken environmental laws ▪ The recent setbacks have not weakened our resolve. ▪ These kinds of contradictions weaken your argument. 2 [no obj] : to become weaker, less forceful, less effective, etc.
▪ The disease causes the immune system to weaken. ▪ The housing market is weakening. [=fewer people are buying houses] 3 of money : to decrease in value when compared to money from other countries [no obj] ▪ The dollar has continued to weaken against the euro. [+ obj] ▪ Lower interest rates have weakened the dollar. — opposite strengthen
▪ The disease weakens the immune system. ▪ people (whose bodies are) weakened by hunger ▪ Some are concerned that the increase in taxes will weaken the economy. ▪ The beams had been weakened by water damage. ▪ efforts to weaken environmental laws ▪ The recent setbacks have not weakened our resolve. ▪ These kinds of contradictions weaken your argument.
▪ The disease causes the immune system to weaken. ▪ The housing market is weakening. [=fewer people are buying houses]
— weakening noun [noncount]
▪ the weakening of environmental laws
▪ the weakening of environmental laws
