1. without excessive behaviour, emotional impact, or flamboyance
I thought I'd make a fairly undramatic farewell.
Vuillard painted small and undramatic domestic scenes in fin-de-siecle Paris.
It was all presented in such a low-key and undramatic fashion.
2. not typical of or suitable for dramatic performance
While the film's been praised by critics, those who don't like it call it undramatic.
What the actor does – lie down, get up, shower, eat – is not scripted and is undramaticin the extreme.