strengthen
Concise Oxford English Dictionary © 2008 Oxford University Press:
strengthen /ˈstrɛŋθ(ə)n, -ŋkθ(ə)n/
▶verb make or become stronger.
– phrases
strengthen someone's hand (or hands) enable a person to act more effectively.
strengthen someone's hand (or hands) enable a person to act more effectively.
– derivatives
strengthener noun.
strengthener noun.
'strengthen' also found in these Oxford entries:

