na-adjective, noun
lacking fixed principles; inconsistent; fickle
Describes a person or attitude that lacks a firm standpoint, easily swayed by circumstances or others' opinions. Often used critically.
彼は無定見で、会議のたびに意見が変わる。
He is inconsistent and changes his opinion at every meeting.
無定見な態度では信頼を得られ
You can't gain trust with a fickle attitude.
一貫性がない is a more general and colloquial way to say 'inconsistent', whereas 無定見 is a formal, literary term focusing on the absence of a fixed opinion.
Compound of 無 (mu, 'without') + 定見 (teiken, 'fixed view'). 定見 itself is a Sino-Japanese word meaning a settled opinion or definite view.