also: てんでんばらばら
na-adjective
various; diverse; divergent; disorderly; uncoordinated
Describes a group of things or people that are all different, scattered, or lacking unity. Often used when opinions, styles, or actions are inconsistent and not aligned.
みんなの意見がてんでバラバラで、まとまらなかった。
Everyone's opinions were all over the place and we couldn't reach a consensus.
彼らの服装はてんでバラバラだった。
Their outfits were completely uncoordinated.
na-adjective
each doing as they please; each according to one's own wishes
Emphasizes that each person acts independently, without coordination or regard for others. Often carries a negative nuance of selfishness or lack of teamwork.
チームなのに、みんなてんでバラバラに動いている。
Even though we're a team, everyone is just doing whatever they want.
まちまち also means 'various' or 'diverse', but is more neutral and simply states that things differ. てんでバラバラ implies a lack of harmony or coordination.
Combination of てんで (each, every) and ばらばら (scattered, in pieces). The exact origin of てんで is uncertain, but it is an emphatic adverbial form. ばらばら is a mimetic word describing a scattered state.