[Bushista] is a recently popular nonce-word, formed by adding the pejorative [-ista] ('follower of', 'acolyte of') to the surname of former US president George W. Bush.
Since the term [Bushista] is used only by opponents of the Bush administration the terms [Bushista[ will normally include meanings such as:
#: lax in the defence of civil liberties;
#: politically opportunistic;
#: uninformed about foreign policy issues;
#: narrowly bigoted (especially about religion);
#: prone to political nepotism.
and so on.