rob·o·rant 
(rŏbər-ənt)
(rŏbər-ənt)adj.
Restoring vigor or strength.
n.
A roborant drug; a restorative or tonic.
[Latin rōborāns, rōborant-, present participle of rōborāre, to strengthen, from rōbur, rōbor-, oak, strength; see reudh- in the Appendix of Indo-European roots.]