"Satisficing" has been in Wikipedia since 2002:

  http://en.wikipedia.org/wiki/Satisficing

and it's in /usr/share/dict/words & the wordnet dictionary.

The OED dates the earliest use in the sense you use to 1957:

  "1956   H. Simon in Psychol. Rev. LXIII. 129/2   Evidently, organisms adapt well enough to ‘satisfice’; they do not, in general, ‘optimize’."

So it is a word :)