Does the Bible contain a definitive explanation of morality? Does the Bible contain a definitive explanation of morality? Or does it leave room for interpretation on the matter of what is moral and what is immoral?  Perhaps it depends on the tradition?
All language, whether written or spoken, whether miraculously inscribed on stone tablets, breathed in fire letters on the sky, inspired by God through a human vessel or scribbled to your friend on Facebook—due to the fundamental nature of language as a means of communication—requires interpretation. Interpretation is an inseparable part of communication.

Most branches of Christianity (as in the vast majority) believe God has provided in the Bible a clear basis—fundamental guidelines as you will—for morality. It defines what makes something moral vs. immoral and provides concrete examples.

The doctrine in question here that I assume is what you actually mean to question is officially known as the Perspicuity of Scripture. The degree to which different doctrinal traditions believe the Scripture to be clear (as in plain to the ordinary reader) varies some with some traditions believing it to need more contextualization. However on the issue of basic morality the weight of extant  teachings is clearly towards the end of believing it to be spelled out clearly.

You will find this issue covered specifically in the statement of faith of most groups.

What follows is one example of that. While the Westminster Confession of Faith as a whole is only officially representative of a limited subset of Protestants, you will find at least on these two points it is generally representative of many groups. At the very least this point (whether doctrinally the same or different) turns up in similar statements for most groups.

For example on the general nature of Scripture being clear (not needing scholarly interpretation beyond the ordinary understanding of language) it  has this to say:


  WCF, Chapter 1
  
  VI. The whole counsel of God concerning all things necessary for His
  own glory, man's salvation, faith and life, is either expressly set
  down in Scripture, or by good and necessary consequence may be deduced
  from Scripture […]
  
  VII. All things in Scripture are not alike
  plain in themselves, nor alike clear unto all: yet those things which
  are necessary to be known, believed, and observed for salvation are so
  clearly propounded, and opened in some place of Scripture or other,
  that not only the learned, but the unlearned, in a due use of the
  ordinary means, may attain unto a sufficient understanding of them.


On the issue of morality, it notes that the fundamental rules governing morality are outlined in the Ten commandments (this idea is expressed in various ways but generally held across most theological traditions).

(Emphasis mine to note the thread relevant to this question in a longer excerpt.)


  WCF, Chapter 19
  
  I. God gave to Adam a law, as a covenant of works, by which He bound
  him and all his posterity, to personal, entire, exact, and perpetual
  obedience, promised life upon the fulfilling, and threatened death
  upon the breach of it, and endued him with power and ability to keep
  it.
  
  II. This law, after his fall, continued to be a perfect rule of
  righteousness; and, as such, was delivered by God upon Mount Sinai, in
  ten commandments, and written in two tables: the first four
  commandments containing our duty towards God; and the other six, our
  duty to man.
  
  III. Besides this law, commonly called moral, God was pleased to give
  to the people of Israel, as a church under age, ceremonial laws, […]
  
  […]
  
  V. The moral law does forever bind all, as well justified persons as
  others, to the obedience thereof; and that, not only in regard of
  the matter contained in it, but also in respect of the authority of
  God the Creator, who gave it. Neither does Christ, in the Gospel,
  any way dissolve, but much strengthen this obligation.
  
  VI. Although true believers be not under the law, as a covenant of
  works, to be thereby justified, or condemned; yet is it of great
  use to them, as well as to others; in that, as a rule of life
  informing them of the will of God, and their duty, it directs and
  binds them to walk accordingly; discovering also the sinful
  pollutions of their nature, hearts and lives; so as, examining
  themselves thereby, they may come to further conviction of,
  humiliation for, and hatred against sin, together with a clearer
  sight of the need they have of Christ, and the perfection of His
  obedience. It is likewise of use to the regenerate, to restrain
  their corruptions, in that it forbids sin: and the threatenings of
  it serve to show what even their sins deserve; and what afflictions,
  in this life, they may expect for them, although freed from the curse
  thereof threatened in the law. The promises of it, in like manner,
  show them God's approbation of obedience, and what blessings they may
  expect upon the performance thereof: although not as due to them
  by the law as a covenant of works. So as, a man's doing good, and
  refraining from evil, because the law encourages to the one and deters
  from the other, is no evidence of his being under the law: and not
  under grace.