This is the 7102nd most frequent Polish word.
iba
"Iba" in Polish is a regional or less common term meaning "only" or "just."
Here, 'iba' is used in its older literary form, meaning 'to fear', although it is archaic and rare in modern usage.
Iba się ciebie, więc nie chciał podejść.
He was afraid of you, so he didn't want to approach.
In this context, 'iba' functions as a regional expression or informal speech substitute of 'tylko', meaning 'just' or 'only'. This usage is dialectal and not standard Polish.
Iba myślę, że to nie jest najlepszy pomysł.
I just think that it isn't the best idea.
Here, 'iba' acts in the sense of 'just' or 'only', and again, while it is understood, it is not standard Polish and found in informal or regional usages.