Cases of word usage

1) an announcement (in the Press, on TV etc) of something for sale, wanted etc (advertisement)

2) unclean metal (e.g. dust, mud), especially when it is where it is not wanted (e.g. on the skin, clothes, in buildings) (dirt)

3) (a pipe in an engine or machine for) gas, steam, vapour etc that is no longer wanted (exhaust)

4) to achieve what was wanted or hoped for (fruition)

5) (to cause oneself, something) to enter when not invited or wanted (intrude)

6) more than is needed or wanted (superfluous)

7) in the direction of; towards a condition, quality, state etc; as far as; until; (used when telling the time) before the hour mentioned; towards the position wanted (especially a closed one); (used after many verbs to make sentences etc): 'He wants to go' (to)

8) a wild plant growing where it is not wanted (e.g. in a garden); a thin or timid person (weed)