in ‧ ac ‧ tion /ɪnˈækʃ ə n/ BrE AmE noun [uncountable]
[ Word Family: noun : ↑ act , ↑ action ≠ ↑ inaction , ↑ activity ≠ ↑ inactivity , ↑ reaction , ↑ interaction , ↑ overacting ; adjective : ↑ acting , ↑ active ≠ ↑ inactive ; verb : ↑ act ≠ ↑ overact ; adverb : ↑ actively ]
the fact that someone is not doing anything:
Several newspapers have criticized the president for inaction.