Had better Meaning, Definition & Usage

Definitions
  1. . (See under Had). The phrase had better, followed by an infinitive without to, is idiomatic. The earliest form of construction was "were better" with a dative; as, "Him were better go beside." (Gower.) i. e., It would be better for him, etc. At length the nominative (I, he, they, etc.) supplanted the dative and had took the place of were. Thus we have the construction now used.
    By all that's holy, he had better starve Than but once think this place becomes thee not. Shak.

Webster 1913