strengthen

1 ENTRIES FOUND:
strengthen /ˈstrɛŋkθən/ verb
strengthens; strengthened; strengthening
strengthen
/ˈstrɛŋkθən/
verb
strengthens; strengthened; strengthening
Britannica Dictionary definition of STRENGTHEN
1 
[+ object] : to make (someone or something) stronger, more forceful, more effective, etc.
2 
[no object] : to become stronger, more forceful, more effective, etc.
3 
of money : to increase in value when compared to money from other countries
[no object]
[+ object]
— opposite weaken