S: (v) guarantee, ensure, insure, assure, secure (make certain of) "This nest egg will ensure a nice retirement for us"; "Preparation will guarantee success!"
S: (v) plug, stop up, secure (fill or close tightly with or as if with a plug) "plug the hole"; "stop up the leak"
S: (adj) secure (not likely to fail or give way) "the lock was secure"; "a secure foundation"; "a secure hold on her wrist"
S: (adj) impregnable, inviolable, secure, strong, unassailable, unattackable (immune to attack; incapable of being tampered with) "an impregnable fortress"; "fortifications that made the frontier inviolable"; "a secure telephone connection"