When Charlotte spoke of lacking boundaries, she likely meant how Evelyn always said things that easily sparked imagination, and did things that easily caused misunderstandings.
For example, she often implied in conversation that taking things a step further would be acceptable, or even outright gifted her bedroom key as a present, deliberately arranging ambiguous times suitable for private meetings, blurring the recipient's understanding of their relationship.
If this were someone more easily aroused, like Lucas, buried a year ago, faced with such an assertive and beautiful mature woman, he'd probably have already schemed to claim this linguistics professor.
