verb (used with object), opposed, opposing.
1. to act against or provide resistance to; combat.
2. to stand in the way of; hinder; obstruct.
3. to set as an opponent or adversary.
4. to be hostile or adverse to, as in opinion: to oppose a resolution in a debate.
5. to set as an obstacle or hindrance.
6. to set against in some relation, especially as to demonstrate a comparison or contrast: to oppose advantages to disadvantages.
7. to use or take as being opposite or contrary.
http://dictionary.reference.com/browse/opposer
In the local churches, the term opposer tends to be used as a noun and not a verb. No one ever defines what is being opposed. It's just a blanket name for anyone who exhibits any concerns or criticisms of what LSM leadership is doing.