restrainer

The development is extremely slow, without any tendency to fog; thus the addition of a restrainer should be avoided.

The non-restrainer is within his right when he practises the system carried to its extremest lengths.

The bromide is a restrainer, and to a certain extent will correct over-exposure.

The restrainer has been withdrawn, and the beast has stepped forth in the plenitude of his power.

For he was zealous, and yet not wanting in knowledge, the restrainer of zeal.