Wordnet 3.0
VERB (1)
1.
make strong again;
The Collaborative International Dictionary of English v.0.48:
Restrengthen \Re*strength"en\, v. t.
To strengthen again; to fortify anew.
[1913 Webster]
WordNet (r) 3.0 (2006):
restrengthen
v 1: make strong again