Disease (motif)
Many of the characters are fixated on disease. Max refers to Ruth as a diseased slut and Lenny tells a story of how he rejected a diseased prostitute. Teddy tries to claim Ruth is "not well." Disease is a way for the characters to articulate that there is something they do not want, something foreign and dangerous, in their midst. Also, disease is ubiquitous in the city and in modern life; it is all the more terrifying because it can be invisible.
Water (motif)
Water is traditionally associated with women and fertility, and Pinter weaves it in frequently in regards to Ruth. She holds a glass of water and uses it to dominate Lenny; she was a model down by the lake; she spent time in Venice with its canals and waterways; and she hates the barren desert of America.
Silence (motif)
Pinter plays with silence and noise, suggesting that sometimes there is more power in the former. Ruth, who becomes the dominant figure in the house, is mute in important moments. She lets Teddy reveal his insecurities when they first arrive. She listens politely to Lenny's attempts to assert his authority, then offers succinct and devastatingly effective responses. She says nothing to Max's frantic queries at the end of the play and remains enshrined in her victorious silence.
The Key (symbol)
When Teddy and Ruth arrive at the family house and prepare to get settled in, Ruth unsettles Teddy by asking for the key to the house so she can take a walk. Teddy is uncomfortable and has difficulty relinquishing this literal and symbolic object; after all, if Ruth can come and go as she pleases in this capacity, what might that mean in a larger sense? Ruth does indeed secure the key and begins her subtle but inexorable push toward domination.
Ruth (symbol)
Ruth is the ultimate symbol of Woman. She is a Mother and a Wife, primarily to Teddy and then, putatively, to the rest of the men in the family. She is a Whore, a Seductress. Her sexuality entices and unsettles; she uses it to get what she wants. She is wily and manipulative, a figure who disrupts the bonds between men.
The story of the prostitute (allegory)
Lenny tells Ruth a story of how a diseased woman tried to take liberties with him and that he contemplated killing her but settled for just beating her. This story is probably only semi-truthful, but it acts as an allegory in that it is intended to impress upon Ruth Lenny's character and capabilities. The woman is "diseased" because he said she is; he does not want her to take advantage of him. He asserts his power, dominance, and strength over her and feels no remorse for doing so. Ruth is supposed to learn that he will do the same for her.
