soft solder vs solder

soft solder and solder both are nouns.

Word	Noun	Adjective	Verb	Adverb
soft solder	Yes	No	No	No
solder	Yes	No	Yes	No

As nouns, solder is a hypernym of soft solder; that is, solder is a word with a broader meaning than soft solder:

soft solder: solder that melts at a relatively low temperature
solder: an alloy (usually of lead and tin) used when melted to join two metal surfaces

soft solder (noun)	solder (noun)
solder that melts at a relatively low temperature	an alloy (usually of lead and tin) used when melted to join two metal surfaces

soft solder (verb)	solder (verb)
	join or fuse with solder