【Full】 , 【complete】 ,  【plenary】 ,  【replete】  are not interchangeable with each other, but the last three are interchangeable with the most comprehensive term,  【full】 , in at least one of its senses.

【Full】  implies the presence or inclusion of everything that is wanted or required by something or that can be held, contained, or attained by it; thus, a  【full】  year numbers 365 days or, in leap years, 366 days; a  【full】  basket is one that can hold nothing more; a  【full】  mind is stocked to the point of overflowing with knowledge or ideas; a  【full】  moon has reached the height of its illumination by the sun; a 【full】 stomach is one that can contain no more food with comfort or is completely satisfied; a  【full】  meal is one lacking in none of the courses or sometimes in none of the elements to make a satisfying or balanced meal; a sponge  【full】  of water has absorbed all the water it can hold.

【Complete】  comes into comparison and close synonymity with  【full】  when the latter implies the entirety that is needed to the perfection, consummation, integrity, or realization of a thing; thus, a fire in which the fuel is quite consumed may be described as involving either  【full】  or  【complete】  combustion; a  【complete】  meal is the same as a  【full】  meal; a teacher should have  【complete】 , or  【full】 , control of his class <if you consider the ritual of the Church during the cycle of the year, you have the  【complete】  drama represented. The Mass is a small drama, having all the unities; but in the Church year you have represented the 【full】 drama of creation —T. S. Eliot >  <the panorama of today’s events is not an accurate or  【complete】  picture, for history will supply posterity with much evidence which is hidden from the eyes of contemporaries —Eliot >

【Plenary】  comes into comparison with  【full】  when  【full】  implies the absence of every qualification or even suggestion of qualification as to a thing’s completeness.  【Plenary】 , however, heightens the force of  【full】  in this sense and carries a stronger suggestion of absoluteness; thus, to give  【plenary】  powers is to give 【full】 power without the slightest qualification; a  【plenary】  indulgence implies the remission of the entire temporal punishment due for one’s sins <by this word "miracle" I meant to suggest to you a something like  【plenary】  inspiration in these … men; an inspiration at once supernatural and so authoritative that it were sacrilege now to alter their text by one jot or tittle —Quiller Couch >

【Replete】  (with), the more bookish term, as compared with  【full】  (of), heightens the implication of abundant supply or of being filled to the brim with something <he is quick, unaffected,  【replete】  with anecdote —Hazlitt >  <an anxious captain, who has suddenly got news,  【replete】  with importance for him —Henry James >  Often, however, the term implies fullness to satiety or to the point of being surfeited <right reading makes a 【full】 man in a sense even better than Bacon’s; not  【replete】 , but 【complete】 rather, to the pattern for which Heaven designed him —Quiller Couch >  < 【replete】 with hard and book-learned words, impressively sonorous —Southern >