An international lecturer is in danger (5)
I believe the answer is:
peril
'in danger' is the definition.
(I've seen this before)
'an international lecturer' is the wordplay.
'an' becomes 'per' (synonymous as in 'once an hour', 'once per hour').
'international' becomes 'i' (abbreviation eg in IMF).
'lecturer' becomes 'l' (abbreviation for lecturer).
'per'+'i'+'l'='PERIL'
'is' acts as a link.
(Other definitions for peril that I've seen before include "Danger, hazard" , "Quest" , "Exposure to harm" , "Hazardous situation" , "Danger, jeopardy" .)