Usage patterns
頑丈な〈物〉a sturdily built object (box, chair, table, etc.)
This table is very sturdy.
頑丈な体a sturdy, robust build (of a person)
頑丈に作るto build something to be sturdy/durable
This bridge is built to be very sturdy.
頑丈なつくりa sturdy construction/design
This safe has a sturdy construction and doesn't break easily.