A warrant is a derivative security that gives the holder the right to purchase securities (usually stocks/shares) from the issuer at a specific price within a certain time frame.
Weighting refers to the proportion of a fund's portfolio held in a particular asset or sector compared with its benchmark or an index. Being 'underweight' is when a fund has a lower percentage weighting in an asset class, stock, sector or geographical region than the index or benchmark against which it is measured. For example, if a fund has a 4% weighting in the technology sector, but its benchmark has a 6.5% weighting, the fund is 2.5% underweight. Conversely, being 'overweight' is when a fund has a greater percentage weighting than the index or benchmark. For example, if a fund has a 5% weighting in the oil and gas sector, but its benchmark has a 3.5% weighting, the fund is 1.5% overweight.