scrumbut [skruhmbut] noun.
1. A person engaged in only partial Agile project management or development methodologies
2. One who engages in either semi-agile or quasi-waterfall development methodologies.
3. One who adopts only SOME tenants of the SCRUM methodology.
4. In general, one who uses the word “but” when answering the question “Do you do SCRUM?”

ScrumButs are the best part of SCRUM makes a great argument that “optimal behavior of a team cannot be predicted” and so retrospectives may be used to tweak SCRUM to optimize it for a particular team. At last a refreshing break from the SCRUM zealots who believe that any deviation from SCRUM is bad and that if you are not doing pure SCRUM then you are not doing SCRUM.

It is worth highlighting that there is a great emphasis on using retrospectives to drive positive optimizations. Pure SCRUM should be adhered to for an iteration or two and then use retrospectives to adjust as necessary for a particular team. The need for an adjustment highlights an aspect of the team behavior that may be different from that envisaged by SCRUM. The team should decide if that behavior is good and should be kept (via a ScrumBut) or if the behavior is bad and if the team should think about a change. Either way the focus is on optimizing the team behavior and this is usually good.