Answer: shoulda

AnswerCrossword Clue
SHOULDAOught to have, informally
SHOULDASlangy word of regret
SHOULDAPart of a colloquial lament
SHOULDAInformal word of regret
SHOULDAOne of three rhyming words of regret
SHOULDAPart of a rhyming rueful triumvirate
SHOULDAWord of regret
SHOULDA"Love ... Brought You Home" (Toni Braxton's first solo hit)
SHOULDAOught to have, in slang
SHOULDA"I ... seen it coming!"