'Serious' in the Bible

So give orders for the sepulchre to be securely guarded till the third day, for fear his disciples should come by night and steal the body, and then tell the people that he has come back to life; and so the last imposture will be more serious than the first."

So there arose a serious disagreement between them, which resulted in their parting from one another, Barnabas taking Mark and setting sail for Cyprus.

Deacons, in the same way, must be men of serious demeanour, not double-tongued, nor addicted to much wine, nor greedy of base gain,

and above all make your own life a pattern of right conduct, having in your teaching no taint of insincerity, but a serious tone,