Is there a term for acting dumb on purpose [duplicate]

Question

I'm looking for a single word of phrase to describe someone intentionally acting dumb or intentionally over looking something obvious so they can deny responsibility or prevent themselves looking bad.

E.g. A person states that they hadn't consider that don't something would have an knock on effect that when the effect is completely obvious and was unlikely to have been overlooked.

I've seen the following suggested: "deliberately obtuse", "passive aggressive" & Blonde in a similar query on Yahoo, but it's not quite what I'm looking for.

Answer 1

Play/act dumb as an idiomatic expression may refer to a deliberate action:

• to pretend to not know or not understand something
  • Don’t play dumb with me – I know you took the money.

(MacMillan Dictionary)

Answer 2

Many terms exists so it's difficult to suggest an appropriate one, but personally I'd go with something like

Understate

1. To state with less completeness or truth than seems warranted by the facts.

Or maybe consider:
downplay

: to make (something) seem smaller or less important

She downplayed [=played down] her role in the research.

Answer 3

Taken from Dictionary.com:

faux-naïf

noun. a person who shrewdly affects an attitude or pose of simplicity or innocence.

Hope this satisfies your needs.