Theory:

Meanings of the difficult words from the poem "Sea Fever":
 
S.No
Words
Meanings
1
DesperatelyUsed to emphasise the extreme degree of something
2
A star to steer The north star is the pole star which tells the sailor where North is and thus they can steer the ship correctly
3
SturdyStrong and healthy; that will not break easily
4
Never-endingSeems to have no end; endless
5
AdventureA thrilling experience
6
DeniedTo refuse to admit or accept something
7
Flung Move or push something suddenly or violently
8
SpumeFroth or foam, especially that found on waves
9
VagrantA person without a settled home or regular work who wanders from place to place
10
WhettedSharpen the blade of a tool or weapon
11
ExaggeratedTo make something seem larger, better than it really is
12
RoverA person who spends their time wandering
13
TrickA period of stay on the ship after the voyage
14
Yarn
A long or rambling story, especially one that is impossible