The tickle capacitor must have been active, because his grin faltered only slightly.

Lewis' grin faltered for just a second, but he turned it into a sneer of defiance.

His grin faltered as he reached inside and withdrew a plastic bag full of human plasma.

The grin didn't falter as the inspector dug out another cigarette and lit it.

His grin faltered at the middle world; he called it Dis.

When they saw me, their grins did not falter, just became more wolflike somehow.

His grin faltered when in the corridor, the four dead men took up the chant.

His grin faltered, and he took a moment before answering.

The grin didn't just falter this time, it slid right off his face.

The Russian soldier's grin never faltered when he heard the translation.