focus vs soak up

focus is a noun but soak up is not a noun.

Word	Noun	Adjective	Verb	Adverb
focus	Yes	No	Yes	No
soak up	No	No	Yes	No

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

Other hyponyms of focus include absorb, engross, engulf, immerse, plunge, steep, recall, think, zoom in, hear, listen, take heed.

focus (noun)	soak up (noun)
maximum clarity or distinctness of an image rendered by an optical system
maximum clarity or distinctness of an idea
the concentration of attention or energy on something
a fixed reference point on the concave side of a conic section
a point of convergence of light (or other radiation) or a point from which it diverges
a central point or locus of an infection in an organism
special emphasis attached to something

focus (verb)	soak up (verb)
become focussed or come into focus	devote (oneself) fully to
put (an image) into focus	take in, also metaphorically
direct one's attention on something
bring into focus or alignment; to converge or cause to converge; of ideas or emotions
cause to converge on or toward a central point