Possible Clues:

• Point and click, e.g.
• Hide and seek, e.g
• Parts of speech
• Stop and go
• They supply all the action in the story
• Come and go, e.g.
• Walk and talk, e.g.?
• Noun followers, often
• Words like iron and lead, perhaps, but not cobalt and tungsten
• Words do have clout ... and lots more!