Difficult to overcome, solve, or decide. / Not settled, uncertain, of uncertain outcome; debatable, questionable, open to doubt.

(chiefly in the plural) A problem or difficulty in a particular field of study.

(mathematics) The mathematical study of probability (the likelihood of occurrence of random events in order to predict the behavior of defined systems).

(computing) The creation, input, editing and formatting of documents and other text using software on a computer.

A device similar to a simple computer, designed for word processing.

In all likelihood.

(mathematical analysis) A sequence in which each term except the first is obtained from the previous by multiplying it by a constant value, known as the common ratio of the geometric progression.

A short and/or incomplete realization of a certain method or idea to demonstrate its feasibility. / (software engineering, perhaps nonstandard) A proof of technology or pilot project.

(idiomatic) Not in a proper or pleasing relation to other things, especially in terms of size.

A particular method for performing a task. / A series of small tasks or steps taken to accomplish an end.