IPA: //ˈkoʊstˌɡɑrdz.mən//
KK: /ˈkoʊstˌɡɑrdzˌmæn/
A person who works for the coast guard, helping to protect the coast and assist in emergencies at sea.
The coastguardsman bravely rescued the stranded boaters during the storm.
Coastguardsman is formed from "coast" (from Old French *coste*, meaning the land beside the sea) and "guardsman" (from "guard" which comes from Old French *guarder*, meaning to keep safe, and "man" meaning a person). The word refers to a person who is responsible for guarding or patrolling the coastal areas.
Think of someone who is a 'person' ('man') that 'guards' ('guarder') the 'land beside the sea' ('coast'). This helps you remember that a coastguardsman is someone who protects coastal regions.
No commonly confused words.