intense phoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticphonetic adjective 

1. extreme and forceful or (of a feeling) very strong 

   intense cold/heat/hatred
    an intense flavour/colour
    What struck her was the intense competition between the two brothers.
    He suddenly felt an intense pain in the lower part of his back.
    At midday the light is at its most intense.

2. A person might be described as intense if they have strong emotions and opinions which they talk
    about very seriously in a way that demands all of your attention. 

   You won't have much of a laugh with Andrew - he's rather intense.

intensely phoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticphonetic adverb 

   His strongest criticism is reserved for his father, whom he disliked intensely.
    She was unimpressed by the actor, describing him as 'a vain man and intensely dull'.

intensity phoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhonetic PhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticphonetic noun [U] 

   His eyes blazed with a passion of such intensity that she was quite alarmed.
    The explosion was of such intensity that it was heard five miles away.

intensifier, intensive phoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhonetic PhoneticPhoneticPhoneticphonetic noun [C] SPECIALIZED 

1. In English grammar, an intensifier is a word, esp. an adverb or adjective, which has little meaning itself
    but is used to add force to another adjective, verb or adverb. 

   In the phrases 'an extremely large man' and 'I strongly object', 'extremely' and 'strongly' are both
   intensifiers.

intensify phoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticphonetic verb 

   It is reported that fighting around the capital has intensified in the last few hours. [I]
    This button on the left of the computer allows you to intensify the colour. [T]

intensification phoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticphonetic noun [U] 

intensive phoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticphonetic adjective 

   Bombing, which was intensive (=continuous and directed at a particular area) in the city centre, 
   has destroyed most of the major buildings.

1. Intensive studying or training is intended to deal with a lot in a short period of time. 

   a month-long intensive course in teaching English

2. In a hospital intensive care is continuous treatment provided for patients who are seriously ill or have
    just had an operation. 

   the intensive-care unit
    She needed intensive care for three weeks.

3. (specialized) Intensive farming uses methods which are intended to produce the largest amount of
    crops or meat possible from a particular area. 

This page is cited from Cambridge Dictionaries Online.  For the original, please visit
http://dictionary.cambridge.org/define.asp?key=intense*1+0