Here are six words you'd better avoid in your proposals. 

1. Best Efforts. Courts have interpreted best efforts to impose a very strict legal obligation, one that goes well beyond a companys normal duty to a client.

Alternative: Reasonable efforts.

2. Ensure. This word may create a binding legal obligation that a client can enforce in court. This word can be particularly dangerous in a T&M project, since it may imply that you are committing to a fixed-price/fixed-time obligation.

Alternatives: Will assist in or will use reasonable efforts to.

3. Guarantee. Using this word essentially amounts to a warranty, and you could be held accountable for it.

Alternative: See No. 2.

4. Partner/Partnership. The word partnership is a legal term meaning, among other things, a relationship in which two parties are liable for each others acts, omissions and debts.

Alternatives: Ally, alliance, or relationship

5. Will meet your needs/requirements. A clients requirements change during the course of a project. For this reason, you should avoid promising that you will meet the clients needs. Courts have held companies liable based on just such promises.

Alternative: Our approach addresses your requirements. Then go on to show how it does.

And Finally   6. Joint/Jointly. These terms may legally imply that a deliverable is a joint work under law; meaning ownership is shared by both parties.

Alternative: Cooperative effort, or cooperatively.