AFTERTHOUGHT
afterthought
(noun) an addition that was not included in the original plan; “the garage was an afterthought”
reconsideration, second thought, afterthought, rethink
(noun) thinking again about a choice previously made; “he had second thoughts about his purchase”
Source: WordNet® 3.1
Etymology 1
Noun
afterthought (plural afterthoughts)
A reflection after an act; a later or subsequent thought, action, or expedient.
Something additional to the original plan or concept.
Verb
afterthought (third-person singular simple present afterthoughts, present participle afterthoughting, simple past and past participle afterthoughted)
(very rare except in the past tense, possibly nonstandard) To expound as an afterthought.
Etymology 2
Verb
afterthought
simple past tense and past participle of afterthink
Source: Wiktionary
Aft"er*thought`, n.
Definition: Reflection after an act; later or subsequent thought or
expedient.
Source: Webster’s Unabridged Dictionary 1913 Edition