ENERVATE: to make someone feel weak and without energy
1.Recuperate:to become well again after an illness; to get back your strength,health, etc.
2.Resurrect:to bring someone back to life
3.Renovate:to repair and improve something ,especially a building
4.Gather:to collect several things, often from different places or people
5.Strengthen: to make something stronger or more effective, or to become stronger or more effective
The answer would be 5.Strengthen.