The tight reg who raises your c-bet on a dry board is not semi-bluffing. There's nothing to semi-bluff with. He has a set or two pair and he's telling you about it.

Why they do it

Dry boards at $1/$2 - rainbow, no draws, disconnected - don't give tight regs anything to semi-bluff with. When they raise a c-bet on a board like K72 rainbow, they're not on a draw. They flopped a monster and they want to build the pot. Believe them.

The adjustment

Fold top pair. Fold two pair on dry boards if the raise is significant. Only continue with sets and better. This is a clear spot and tight regs at $1/$2 are not making moves here.

What it's worth

Calling a tight reg's check-raise on a dry board with top pair and paying off two more streets costs you $150+. One correct fold here per session is meaningful money saved.