improve vs pick up

improve and pick up both are verbs.

Word	Noun	Adjective	Verb	Adverb
improve	No	No	Yes	No
pick up	No	No	Yes	No

As verbs, pick up is a hyponym of improve; that is, pick up is a word with a more specific, narrower meaning than improve:

improve (verb)	pick up (verb)
get better	gain or regain energy
to make better	improve significantly; go from bad to good
	lift out or reflect from a background
	get to know or become aware of, usually accidentally
	eat by pecking at, like a bird
	take into custody
	take up by hand
	fill with high spirits; fill with optimism
	give a passenger or a hitchhiker a lift
	take and lift upward
	perceive with the senses quickly, suddenly, or momentarily
	register (perceptual input)
	buy casually or spontaneously
	gather or collect
	get in addition, as an increase
	meet someone for sexual purposes