The definition below refers to Adaptation to Climate Change.
The RESIN project  gives the following definition:
The degree to which a system or species is affected, either adversely or beneficially, by climate variability or change. The effect may be direct...or indirect. 
The IPPC's risk framework considers Vulnerability to be comprised of sensitivity and Adaptive Capacity.
Other International Definitions
Sensitivity denotes the extent to which a natural or artificial system can be influenced by climate change. Some changes act directly, others indirectly. 
Sensitivity: The degree to which a system is affected, either adversely or beneficially, by climate-related stimuli. 
Sensitivity determines the degree to which a system is adversely or beneficially affected by a given climate change exposure. 
Sensitivity – in the context of climate change, the degree to which a system is affected, either adversely or beneficially, by climate variability or change. 
Sensitivity is a measure of the importance assigned to information by its owner, for the purpose of denoting its need for protection. (from: NIST SP 800-30) 
Sensitivity is the degree to which an IT system or application requires protection (to ensure confidentiality, integrity, and availability) which is determined by an evaluation of the nature and criticality of the data processed, the relation of the system to the organization missions and the economic value of the system components.
(from: NIST SP 800-16) 
- ↑ http://www.resin-cities.eu/
- ↑ Mach, K.J., S. Planton and C. von Stechow (eds.). Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Annex II: Glossary. [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)]. IPCC, Geneva, Switzerland, pp. 117-130.
- ↑ Combating Climate Change: The German Adaptation Strategy
- ↑ Climate Change and Community Based Adaptation Planning Training Manual, Government of Nepal (2015)
- ↑ BASELINE CLIMATE CHANGE VULNERABILITY INDEX FOR RWANDA 2015
- ↑ The National Adaptation Programme: Making the country resilient to a changing climate, UK Government (2013)
- ↑ 7.0 7.1 NIST Glossary