Inconstancy

/ˌɪn.kənˈstæn.si/

Synonyms

  • capriciousness
  • changeability
  • fickleness
  • unreliability
  • variability

Slang Meanings

Wishy-washy
He's so wishy-washy; he can't stick to one idea for more than a minute.
Flaky
Don't count on him to show up; he's pretty flaky when it comes to plans.