### Clue: Learn? I can't — lacking time for observation and application (6)
### Answer: ARNICA 
 ### Explanation: Definition: application
A subtraction: '[le]ARNICA[nt]' minus ('lacking') LENT ('time of observation' before Easter). Arnica is a genus in the sunflower family; an extract of the flowers of some species has been used as an 'application' to treat bruises.