ADJ

heavy
gentle, slight
10-foot, 20-foot, etc.
Atlantic, ocean
bobbing up and down like a small boat in a heavy ocean swell

SWELL + VERB

break, come/roll in, lift sb/sth, surge up
The Atlantic swell surged up under them

PREP

in a/the ~
The trawler rolled wildly in the heavy swell
on/with the ~
The boat rose and fell with the swell

ADJ

firm, gentle, soft, warm

PREP

~ of
the gentle swell of her breasts