buckˈler noun

1. A small shield used in parrying
2. A protector, protection

To protect, shield

buckˈle-beggar noun (Scot hist)

A person who performed marriages without a licence

buckler fern noun

A European fern of the genus Dryopteris

buckle down

To apply oneself zealously (to)

buckle to

To buckle down to

buckle under

To give in or collapse under strain