thermodynamics

to study / to learn

deep, profound

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend

he; boyfriend

fever / (physics) heat

(transitive) to heat up / (intransitive) to heat

deep, close, thick, profound

deep, profound