I think we would need to know the context to say if you have interpreted the word correctly.
If you said 'movement' in a military context, such as 'The army scout noticed the enemy movement and reported them to his General.' Then I would say your interpretation is correct.
However 'movement' can also mean a campaign by people, or a group of people working together for a purpose. For example there are animals' rights 'movements'.
In your example, 'The movement against occupying forces was getting stronger.' I would say 'movement' refers to a civilian uprising or protest, much like what is happening in the Middle East. Or, how people resisted Nazi rule in World War Two, such as the French Resistance movement.
Hope this helps.
EDIT: Realised spelling mistake.