The antonyms for the phrase "keeps arm length" could include terms like "closeness," "proximity," or "nearness." These words suggest a level of intimacy or familiarity that is the opposite of maintaining distance. Another possible antonym could be "attachment," which implies a strong emotional bond or connection with someone or something. Other antonyms might include terms like "united," "reliant," or "cooperative," which all suggest a degree of interdependence or teamwork that differs from the independent, self-sufficient attitude implied by "keeps arm length." Ultimately, the specific antonyms that are most appropriate will depend on the context in which the phrase is being used.