The best replacement for object is subject.

The best alternatives to object are rated as following:
★★★★★  subject
★★★★  class
★★★★  embed
★★★  iframe
★★  indirect object
★  method
★  array
★  instance
★  unstoppable force
★  class java
★  direct object
★  complement
  array javascript
  struct
  subject grammar
  var
  object of the preposition
  object c
  object c#
  entity
  object of a preposition
  subject complement
  class definition
  module
  relational

Your alternative for object is not listed? Suggest!
Speaking about object, one probably shouldn't forget about touching it.

Other search terms related to object and their ratings are:
★★★★★ touching it
★★★ direct object
★★ class
You have in mind a companion for object and it is not yet here? Propose!



Google Trends

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object
subject
class