Adjective
1. safe
2. fail-safe, harmless, innocuous, off the hook, risk-free, riskless, unhazardous, safe and sound, unhurt, harmless, invulnerable, secure, uninjured, unadventurous
3. safe
4. dependable
5. good, secure, sound, secure
Noun
1. strongbox
2. deedbox, cupboard
3. closet, condom
3. rubber, safety, prophylactic, contraceptive, preventive, preventative, contraceptive device, prophylactic device, birth control device